Engineering Windows 7

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User Account Control

User Account Control

We promised that this blog would provide a view of Engineering Windows 7 and that means that we would cover the full range of topics—from performance to user interface, technical and non-technical topics, and of course easy topics and controversial topics.  This post is about User Account Control.  Our author is Ben Fathi, vice president for core OS development.  UAC is a feature that crosses many aspects of the Windows architecture—security, accounts, user interface, design, and so on—we had several other members of the team contribute to the post. 

We continue to value the discussion that the posts seem to inspire—we are betting (not literally of course) that this post will bring out comments from even the most reserved of our readers.  Let’s keep the comments constructive and on-topic for this one.

FWIW, the blogs.msdn.com server employs some throttles on comments that aim to reduce spam.  We don’t control this and have all the “unmoderated” options checked.  I can’t publish the spam protection rules since that sort of defeats the purpose (and I don’t know them).  However, I apologize if your comment doesn’t make it through.  --Steven

User Account Control (UAC) is, arguably, one of the most controversial features in Windows Vista. Why did Microsoft add all those popups to Windows? Does it actually improve security? Doesn’t everyone just click “continue”? Has anyone in Redmond heard the feedback on users and reviewers? Has anyone seen a tv commercial about this feature? 

In the course of working on Windows 7 we have taken a hard look at UAC – examining customer feedback, volumes of data, the software ecosystem, and Windows itself. Let’s start by looking at why UAC came to be and our approach in Vista.

The Why of UAC

Technical details aside, UAC is really about informing you before any “system-level” change is made to your computer, thus enabling you to be in control of your system. An “unwanted change” can be malicious, such as a virus turning off the firewall or a rootkit stealthily taking over the machine. However an “unwanted change” can also be actions from people who have limited privileges, such as a child trying to bypass Parental Controls on the family computer or an employee installing prohibited software on a work computer. Windows NT has always supported multiple user account types – one of which is the “standard user,” which does not have the administrative privileges necessary to make changes like these. Enterprises can (and commonly do) supply most employees with a standard user account while providing a few IT pros administrative privileges. A standard user can’t make system level changes, even accidentally, by going to a malicious website or installing the wrong program. Controlling the changes most people can make to the computer reduces help desk calls and the overall Total Cost of Ownership (TCO) to the company. At home, a parent can create a standard user account for the children and use Parental Controls to protect them.

However, outside the enterprise and the Parental Controls case, most machines (75%) have a single account with full admin privileges. This is partly due to the first user account defaulting to administrator, since an administrator on the machine is required, and partly due to the fact that people want and expect to be in control of their computer. Since most users have an Administrator account, this has historically created an environment where most applications, as well as some Windows components, always assumed they could make system-level changes to the system. Software written this way would not work for standard users, such as the enterprise user and parental control cases mentioned above. Additionally, giving every application full access to the computer left the door open for damaging changes to the system, either intentionally (by malware) or unintentionally (by poorly written software.)

Percentage of machines (server excluded) with one or more user accounts from January 2008 to June 2008.  75% of machines have one account.

Figure 1. Percentage of machines (server excluded) with one or more user accounts from January 2008 to June 2008.

User Account Control was implemented in Vista to address two key issues: one, incompatibility of software across user types and two, the lack of user knowledge of system-level changes. We expanded the account types by adding the Protected Admin (PA), which became the default type for the first account on the system. When a PA user logs into the system, she is given two security tokens – one identical to the Standard User token that is sufficient for most basic privileges and a second with full Administrator privileges. Standard users receive only the basic token, but can bring in an Administrator token from another account if needed.

When the system detects that the user wants to perform an operation which requires administrative privileges, the display is switched to “secure desktop” mode, and the user is presented with a prompt asking for approval. The reason the display is transitioned to “secure desktop” is to avoid malicious software attacks that attempt to get you to click yes to the UAC prompt by mimicking the UAC interface (spoofing the UI.) They are not able to do this when the desktop is in its “secure” state. Protected Admin users are thus informed of any system changes, and only need to click yes to approve the action. A standard user sees a similar dialog, but one that enables her to enter Administrative credentials (via password, smart card PIN, fingerprint, etc) from another account to bring in the Administrator privileges needed to complete the action. In the case of a home system utilizing Parental Controls, the parent would enter his or her login name and password to install the software, thus enabling the parent to be in control of software added to the system or changes made to the system. In the enterprise case, the IT administrator can control the prompts through group policy such that the standard user just gets a message informing her that she cannot change system state.

What we have learned so far

We are always trying to improve Windows, especially in the areas that affect our customers the most. This section will look at the data around the ecosystem, Windows, and end-users—recognizing that the data itself does not tell the story of annoyance or frustration that many reading this post might feel. 

UAC has had a significant impact on the software ecosystem, Vista users, and Windows itself. As mentioned in previous posts, there are ways for our customers to voluntarily and anonymously send us data on how they use our features (Customer Experience Improvement Program, Windows Feedback Panel, user surveys, user in field testing, blog posts, and in house usability testing). The data and feedback we collect help inform and prioritize the decisions we make about our feature designs. From this data, we’ve learned a lot about UAC’s impact.

Impact on the software ecosystem

UAC has resulted in a radical reduction in the number of applications that unnecessarily require admin privileges, which is something we think improves the overall quality of software and reduces the risks inherent in software on a machine which requires full administrative access to the system.

In the first several months after Vista was available for use, people were experiencing a UAC prompt in 50% of their “sessions” - a session is everything that happens from logon to logoff or within 24 hours. Furthermore, there were 775,312 unique applications (note: this shows the volume of unique software that Windows supports!) producing prompts (note that installers and the application itself are not counted as the same program.) This seems large, and it is since much of the software ecosystem unnecessarily required admin privileges to run. As the ecosystem has updated their software, far fewer applications are requiring admin privileges. Customer Experience Improvement Program data from August 2008 indicates the number of applications and tasks generating a prompt has declined from 775,312 to 168,149.

Number of unique applications and tasks creating UAC prompts.  Shows a significant decline.

Figure 2. Number of unique applications and tasks creating UAC prompts.

This reduction means more programs work well for Standard Users without prompting every time they run or accidentally changing an administrative or system setting. In addition, we also expect that as people use their machines longer they are installing new software or configuring Windows settings less frequently, which results in fewer prompts, or conversely when a machine is new that is when there is unusually high activity with respect to administrative needs. Customer Experience Improvement Program data indicates that the number of sessions with one or more UAC prompts has declined from 50% to 33% of sessions with Vista SP1.

Percentage of sessions with prompts over time. 

Figure 3. Percentage of sessions with prompts over time.

Impact on Windows

An immediate result of UAC was the increase in engineering quality of Windows. There are now far fewer Windows components with full access to the system. Additionally, all the components that still need to access the full system must ask the user for permission to do so. We know from our data that Windows itself accounts for about 40% of all UAC prompts. This is even more dramatic when you look at the most frequent prompts: Windows components accounted for 17 of the top 50 UAC prompts in Vista and 29 of the top 50 in Vista SP1. Some targeted improvements in Vista SP1 reduced Windows prompts from frequently used components such as the copy engine, but clearly we have more we can (and will) do. The ecosystem also worked hard to reduce their prompts, thus the number of Windows components on the top 50 list increased. Windows has more of an opportunity to make deeper architectural changes in Windows 7, so you can expect fewer prompts from Windows components. Reducing prompts in the software ecosystem and in Windows is a win-win proposition. It enables people to feel confident they have a greater choice of software that does not make potentially destabilizing changes to the system, and it enables people to more readily identify critical prompts, thus providing a more confident sense of control.

One important area of feedback we’ve heard a lot about is the number of prompts encountered during a download from Internet Explorer. This is a specific example of a more common situation - where an application’s security dialogs overlap with User Account Control. Since XP Service Pack 2, IE has used a security dialog to warn users before running programs from the internet. In Vista, this often results in a double prompt – IE’s security dialog, followed immediately by a UAC dialog. This is an area that should be properly addressed.

Number of Microsoft prompters in the top 50 over time.

Figure 4. Number of Microsoft prompters in the top 50 over time.

Impact on Customers

One extra click to do normal things like open the device manager, install software, or turn off your firewall is sometimes confusing and frustrating for our users. Here is a representative sample of the feedback we’ve received from the Windows Feedback Panel:

  • “I do not like to be continuously asked if I want to do what I just told the computer to do.”
  • “I feel like I am asked by Vista to approve every little thing that I do on my PC and I find it very aggravating.”
  • “The constant asking for input to make any changes is annoying. But it is good that it makes kids ask me for password for stuff they are trying to change.”
  • “Please work on simplifying the User Account control.....highly perplexing and bothersome at times”

We understand adding an extra click can be annoying, especially for users who are highly knowledgeable about what is happening with their system (or for people just trying to get work done). However, for most users, the potential benefit is that UAC forces malware or poorly written software to show itself and get your approval before it can potentially harm the system.

Does this make the system more secure? If every user of Windows were an expert that understands the cause/effect of all operations, the UAC prompt would make perfect sense and nothing malicious would slip through. The reality is that some people don’t read the prompts, and thus gain no benefit from them (and are just annoyed). In Vista, some power users have chosen to disable UAC – a setting that is admittedly hard to find. We don’t recommend you do this, but we understand you find value in the ability to turn UAC off. For the rest of you who try to figure out what is going on by reading the UAC prompt , there is the potential for a definite security benefit if you take the time to analyze each prompt and decide if it’s something you want to happen. However, we haven’t made things easy on you - the dialogs in Vista aren’t easy to decipher and are often not memorable. In one lab study we conducted, only 13% of participants could provide specific details about why they were seeing a UAC dialog in Vista.  Some didn’t remember they had seen a dialog at all when asked about it. Additionally, we are seeing consumer administrators approving 89% of prompts in Vista and 91% in SP1. We are obviously concerned users are responding out of habit due to the large number of prompts rather than focusing on the critical prompts and making confident decisions. Many would say this is entirely predictable.

Percentage of prompts over time per prompt type.

Figure 5. Percentage of prompts over time per prompt type.

Percentage of UAC prompts allowed over time.

Figure 6. Percentage of UAC prompts allowed over time.

Looking ahead…

Now that we have the data and feedback, we can look ahead at how UAC will evolve—we continue to feel the goal we have for UAC is a good one and so it is our job to find a solution that does not abandon this goal. UAC was created with the intention of putting you in control of your system, reducing cost of ownership over time, and improving the software ecosystem. What we’ve learned is that we only got part of the way there in Vista and some folks think we accomplished the opposite.

Based on what we’ve learned from our data and feedback we need to address several key issues in Windows 7:

  • Reduce unnecessary or duplicated prompts in Windows and the ecosystem, such that critical prompts can be more easily identified.
  • Enable our customers to be more confident that they are in control of their systems.
  • Make prompts informative such that people can make more confident choices.
  • Provide better and more obvious control over the mechanism.

The benefits UAC has provided to the ecosystem and Windows are clear; we need to continue that work. By successfully enabling standard users UAC has achieved its goal of giving IT administrators and parents greater control to lock down their systems for certain users. As shown in our data above, we’ve seen the number of external applications and Windows components that unnecessarily require Admin privileges dramatically drop. This also has the direct benefit of reducing the total amount of prompts users see, a common complaint we hear frequently. Moving forward we will look at the scenarios we think are most important for our users so we can ensure none of these scenarios include prompts that can be avoided. Additionally, we will look at “top prompters” and continue to engage with third-party software vendors and internal Microsoft teams to further reduce unnecessary prompts.

More importantly, as we evolve UAC for Windows 7 we will address the customer feedback and satisfaction issues with the prompts themselves. We’ve heard loud and clear that you are frustrated. You find the prompts too frequent, annoying, and confusing. We still want to provide you control over what changes can happen to your system, but we want to provide you a better overall experience. We believe this can be achieved by focusing on two key principles. 1) Broaden the control you have over the UAC notifications. We will continue to give you control over the changes made to your system, but in Windows 7, we will also provide options such that when you use the system as an administrator you can determine the range of notifications that you receive. 2) Provide additional and more relevant information in the user interface. We will improve the dialog UI so that you can better understand and make more informed choices. We’ve already run new design concepts based on this principle through our in-house usability testing and we’ve seen very positive results. 83% of participants could provide specific details about why they were seeing the dialog. Participants preferred the new concepts because they are “simple”, “highlight verified publishers,” “provide the file origin,” and “ask a meaningful question.” 

In summary, yes, we’ve heard the responses to the UAC feature – both positive and negative. We plan to continue to build on the benefits UAC provides as an agent for standard user, making systems more secure. In doing so, we will also address the overwhelming feedback that the user experience must improve.

Ben Fathi

Leave a Comment
  • Please add 7 and 2 and type the answer here:
  • Post
  • >>Of course, I'm still not going to use it if you keep that horrible Vista Explorer. XP's was 99% perfect, apart from its intransigent refusal to display folder sizes.

    I'm sure if they made a post on the UI/Explorer we'd crash their servers with responses. :) We have much to say. lol

    >>The ones that I have seen have been useless, though, in that they don't give me any useful information about what's really going on.

    I love UAC but, generally, the prompts do look rather vague and useless. Makes me interested to see what they're doing with these new UAC dialogs for W7.

  • Personally, I'd like to see the transition to UAC prompts a bit more smooth.  I realize the importance of using secure desktop, but the way the screen flashes is really annoying.  Some kind of smooth fade would be a huge improvement!

    Also, I'd like to see the ability to "open files as administrator."  For example, if I want to edit a file in Program Files, I have to first run the editor with elevated privileges, then navigate to and open the file.  I'd much rather do that in one click.

    P.S. I'm one of the few Vista users I know who have left UAC enabled; I think it's useful, if a bit annoying at times.

  • I bought a computer with Windows Vista within the first few days of its release.  UAC was the first thing about Vista that I noticed when I started using it.  After fighting off Malware on Windows 98 and Windows Xp machines for so long, and so many futile hours of trying to sanitize the compromised machines of friends and families, I immediately appreciated what you guys were doing with UAC.  It is absolutely necessary and I'm glad to hear that you will bring an improved version of UAC to the next version of Windows.

  • One easy tweak that could eliminate many UAC prompts would be make a "Programs" folder inside the "User" folder. Make it easy for installers to give an option switch to this alternative "Programs" directory before the UAC popup is presented. Right now applications let either let you choose a folder or default to the "Application Data" folder (See sync-toy).

    Overall UAC is a great idea, it just has some rough edges and needs more support by making user specific copies of system directories.

    One graph that I would like to see is the % of people with UAC turned off. From comments on forums it sounds like many people have it turned off, but in my experience I have found very few people with it off.

  • One of the things I would like added is an "Approved List" for the UAC.  There are a couple pieces of software, mainly updaters, that prompt a UAC message each time the program runs.  I know what these programs are and I will always approved each time.  

    If there was a list that users could add programs to that would allow the programs to either bypass the UAC or send an approved response to it automatically it will be great.  Putting programs on this list should not be easy but it should not be difficult either.  Maybe a right click, run as admin, then check mark in the admin login box would work.  Programs should not be allowed to place themselves or other programs onto this list.

  • It took me a while to get around to using UAC but now that i know how to use it correctly i really dig it, well done! The only problem i have with it is with the secure desktop, when it’s activated it’s sort of a jarring experience, almost akin to a system crash. Would it be possible to maybe smooth the transition somewhat, my nerves are not what they were lol

  • Microsoft has a free software called Steady State. This is a kid safe environment. It doesn't save any changes to the computer. I think MS should consider it build-in.

    About UAC, it is fine. I am using it to know what the installer is modifying important sector or not. But sometimes it is quite annoying indeed.

  • One of the things I really think would reduce complaints would be if once you okayed a UAC prompt the user wouldn't be prompted for another 30 seconds or minute. I know that for me at least the prompts tend to come in bursts, and if I only have to click once instead of the 5 or so times in a row, that would make me appreciate UAC much more.

  • I have been running separate accounts since Windows 2000. I know how my system works and keep it running like clockwork. I was happy without UAC and hoped it would not affect me. With every system I gave UAC a fair chance, but had to turn it off every time.

    The popups are annoying, but far worse is when UAC fails silently. For no apparent reason, actions fail to execute, files are not created where they are supposed to, applications crash.

    Example 1: change the source viewer in IE7 to VIM, then choose "View source", then nothing happens.

    Example 2: installation of a mission-critical software package fails with UAC on, even with administrator rights. The installer tries to copy its "ini" to the Windows folder.

    Example 2: game modification installer, properly designed to work with restricted rights, crashes with UAC on. File creation operations succeed, but the files are not created, at least not where they are expected.

    It does not stop there. Even when off, UAC is a major pain. Things that worked fine in XP break. RunAs no longer works. Cardspace fails.

    UAC is appalling.

  • Windows Steady State is very very good, especially if you have kids in the home.

    Implementing a feature or at least a link to the download location in the Parental Controls would be very very helpful.

  • I have always had user account control on, and I don't mind it too much. The security makes up for the annoyance...most of the time. There are certain things which bring up WAY too many UAC prompts.

    For example: I want to manually delete a folder from C:/Program Files. First, I have to click "Yes" to confirm that I really wanted to delete it. Then I have to click "Continue" because I am modifying C:/Program Files. Clicking that brings up UAC, where I have to click "Continue" again.

    Sorry, but that is too many prompts. There should a maximum of ONE prompt after I confirm the deletion. This prompt would tell you why it had appeared ("Modifying C:/Program Files could cause undesirable program errors. Click continue if you are sure you want to delete this folder.")

    ...Just one example of excess annoyance. I agree with the previous posts that when users see too many prompts, they stop reading them and just click continue.

    Keep up the great work!

  • Of course, so many people complain about the secure desktop (jarring screen 'crash', etc.) and there is a group policy setting that can turn it off (google "turn off secure desktop") while still leaving uac on. This really tells you something about the people who sit around on forums criticizing MS all day, and what they know.  Anyway, I like UAC as it is, I only see a uac screen when I am doing system wide changes that I want software not to be able to do without my permission.  Compromising UAC would mean any software could do anything it wanted on my system, I can't believe people even suggest that, they should go turn off uac and leave everyone else alone with that asinine nonsense.  One thing I would like to see is a no-read-up policy for low integrity level on most everything.  As it is now, malware can't write to the system areas and auto-start with windows and so on, but it can still read user data and this is a security concern MS should address. MS should notify developers that this will go into effect in Windows 7 so that they have time to fix whatever code this affects and then set it up like that so that users don't have valuable private data stolen by any malware that exploits IE. Thanks for the blog and good work, again.

  • >> I don't know if the screen blank is a result of my hardware or device drivers or is caused by the OS itself but by getting rid of this one artifact would improve my UAC experience by an order of magnitude.

    It is your hardware.  Is your monitor connected via VGA by chance?  When Windows resets the video mode, VGA monitors have to resync and that takes time.  DVI monitors don't have this problem.

    Why it resets the video mode I still haven't figured out, there has to be a way to have a secure desktop without the video driver needing to know.

    >> Example 1: change the source viewer in IE7 to VIM, then choose "View source", then nothing happens.

    Just an aside, you are enough of a power user to use VIM (heck, even know what VIM is) and you still use IE for anything where viewing source matters?  You are probably one in a million.  The rest of us left that piece of trash long ago and only use it for that one percent of the web that hasn't figured out what standards mean.

    Directly on topic, I really think the UAC developers should put Windows away for a month and go use either OS X or Linux.  Experience sudo and how it works.  Return to Windows development, throw out UAC entirely, and as Apple would say, "start your photocopiers."

    Duplicate prompts aren't a problem, the user is allowed to do anything that affects only them without a prompt, and the prompts that you do get have this nifty button titled "Details" which when clicked tells you what wants privs and why.  If you're having prompts being automatically triggered by requests to change certain things, clearly the software knows what triggered it and can tell me so I don't have to guess.

  • I believe this three points would be very usefull to improve UAC:

    1- If i check an application to run always as an administrator... why i need to aprove it every time? whit just once uthorization would be great.

    2- Detect when a user makes changes and when another source make the changes (virus, malware, other apps no directly opened by users etc.) UAC must be less extrict when the action is made it directly by an admin user.

    3- Create 'UAC - permisson groups', may be i need my kids or my workers can change some 'less dangerous' configurations, but not anothers.

  • Isn't this just like the boy who cried wolf story?

    Now that Vista has been out for a while and people have become used to the "excessive" UAC prompts isn't it kinda too late to train people to pay attention to these prompts.  I can see if people jumped from XP to Windows 7 you could easily instill in users that if you see a UAC prompt pay close attention to it.  But for users going from Vista to 7 isn't it already too late?  Windows 7 users coming from XP may respond correctly but Vista users would think "oh it's just that unnecessary UAC prompt again" and hit continue and then allow the malware to run.

    If I could request certain areas for UAC not to be enabled it would be the Reliability and Performance Monitor cause what setting can you adjust there?  None that I know of.  When adjust the date and time.  When you install update from Windows Update.  On that subject why don't we get UAC prompts when Windows automatically installs updates itself during a shutdown or restart?

    Slightly OT but I'd like to remove the dialog box that pops up when you move something to the recycle bin asking if I'm sure I want to do this.  I understand why you do this but I'd like the option to turn this off.

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