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 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
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  • The idea of the UAC is right, but you need to work in options like "I Trust in this software" so the UAC don't display every time the popup.... and please avoid duplicate popup, i receive in some circunstancies three popup for one operation ???

  • I'm using Windows Live OneCare and have choosen to manually allow software to access the internet. When a new software want's to access the internet, I'll get 3 promts on Vista. First OneCare asking to allow this, then UAC asking to allow OneCare to allow this, and then again OneCare asking the same question again. Please make your own software work better with UAC. This task should be only one click. If it's UAC or OneCare asking doesn't matter. But it should be only one click.

    I don't know if this has been fixed in SP1 as I've not tried it again. When I tried to sort my start menu programs on Vista (without SP1) by moving, deleting and renaming the shortcuts, I've got for every single action and shortcut an UAC prompt. I simply gave up sorting my start menu (the nice Vista menu with search box helps a lot with an unsorted menu).

    Sometimes the UAC promt starts minimized or in the background. I see only the flashing button in the taskbar and I have to click it to bring it into the foreground. An unexperienced user may miss this and never see the promt and wonder why the action he wants to start doesn't work.

    I want a feature that I can disable UAC promts for a specific action (e.g. a checkbox in the UAC dialog "Never ask me for this action again"). So I can partially disable UAC for often used programs or actions. This could work similary like a firewall. As soon as the program changes (filesize/hash/location), the UAC promt will return.

  • I think I caught the basic Idea of UAC already in the first Vista beta. But as a so called 'Poweruser' I tend to turn the whole thing off, as soon as the installation is finished.

    so, instead of controlling ALL of my action, or rather respond to always the same action, it would be great if the UAC had some sort of Training Mode..

    You see that in Firewalls a lot, where the software 'tries to get an idea' of how people use the network, Ports etc...

    (or at least that you would have some kind of option, that UAC remembers the choice I've made...).

  • I think it would be good to have some visual cue (like an alternatively colored title-bar or maybe a small icon), that makes clear that a program runs in elevated mode.

    On a side note: I'm wondering how people are using their client-systems when the UAC-prompt is such a huge cause of anoyance. Although I consider myself a power user, I don't see many prompts as there's no need to change system-settings (or install software) on a daily basis.

  • Only one thing to say, keep the system protected by default but give possibility to desactivate this security. User mustn't be jailed with something he don't want.

  • One thing that I don't know why more people don't complain about is UAC and networking. Other then the "ipconfig /renew" not working without running cmd with Run as... UAC and networking is my next most fustrating issue. For example, you are trying to run an application install off the network. Now in order to correctly install the software you are asked to "Run with higher rights" that of a local admin account. In a domain that local admin account does not have access to the files needing to be installed so the whole installation fails. Now some of you smarty pants might say well you should have been using group policy using msi's to deploay the software anyways!. There are still a lot of vendors that do not provide an MSI and sometimes I have seen where if the program itself does automatic updates like Adobe reader group policy sometimes kicks back in and tries to re-install the application which then completely renders the program useless. What I propose that Microsoft first an formost is make their OS have the ability to have a regular user have a UAC type prompt that asks them for permission of the administrator. So many programs break if the user isn't an administrator. Although I hate to say it Linux and Mac OS do such a better job at this then compared with Windows. If the UAC gave the option to check off a box and then be able to specify an adim like "administrator@domain.local" that would really help us out. UAC is great for home users... terible for Domains...

  • I'm waiting a post about WGA. I hope you are able to provide a good protection against privacy for Windows. I don't why a big company like you unable to win against a small team of hackers. Or, maybe you deliberately giving chance to piracy in order to widespread Windows usage in third world countries which most of users unable or unwilling to buy a freaking expensive license of Windows. If what I'm saying is not right, I guess you know what you have to day. I'll keep viewing this blog and hope you will make a good post to explain your view on piracy and your anti-piracy strategy. Hope you'll have a good implementation too.


  • The problem with UAC is that it's not just the UAC prompts. Turning UAC off stops file and registry virtualisation, knackering up user settings and configurations in many programs (especially if you only have UAC on intermittently). Likewise this works in reverse. With UAC turned on, why is the DRM registry files around htcaccess hidden (even with "view hidden files" turned on)? - users sadly need to get there quite a bit to delete those files as the DRM registry is so prone to corruption, and if they do they have no idea that they're failing to do so unless they're running with UAC turned off - this forces three reboots for a task that should only take one.

    WHY!!! It's baffling. UAC being on or off should control UAC only. It shouldn't randomly be changing file permissions and virtualisation at it's whim.

  • I simply hate the UAC prompts. I'd prefer to get a plain old "Access denied" message. You already have the "Run as Administrator" option on right-click on all applications. I can even put that as a default if I wish. A bit better "sudo" support would be great.

    The problem is that if I run as a normal user with UAC turned off a lot of stuff just failes silently (especially registering ActiveX's with regsvr32.exe during install of apps). The application seemingly was installed fine, but when I start it up it failes due to missing ActiveX components.

  • Can't Windows implement something similar to SUID bit on Unix/Linux system?

    As a developer, most of time I am forced to create a do-nothing service simply for giving auto-elevation to my application. An Unix-like SUID feature will eliminate the need for creating services in such kind of scenario and reduce the number of services running on the system.

    On Windows, one can set the flag "Run As Administrator" on an executable file. But Windows would prompt for credential when starting such file. I *really* hate this.

  • My thoughts on UAC:

    As an IT professional, I keep a good idea of what's going on for my system at all times, so UAC was an extreme annoyance for me.  I'll admit I took the time to find the settings and disable it.  I do appreciate Microsoft biting the bullet though and forcing the lazy application developers out there to actually think about what kind of access their programs really need.  The side benefit we noticed is that it's been a lot easier to secure our Terminal Services farms now because a lot of the applications aren't fussy about requiring local administrator group privileges (this used to be a huge pain).  Overall I like the direction Microsoft is taking, as they've let the developer community be too lazy for too long, but keep this blog going, as I think every time you guys can explain why you're doign things with Windows Vista and Windows 7 in a particular way, you'll help us understand, and you'll get better buy-in from us in the IT pro community.

  • In general, I actaully really like UAC. So much so that I enable the 'Administrator' account in Vista and set my personal account to be a 'Standard User'. So not only do I get a UAC prompt, I have to type a different password in to allow that change. I like to think of it as similar to the security on a Mac or Ubuntu machine.

    As many others, I'm sure, I do have my gripe with UAC, though, and the Windows 7 team seems to know about them already:

    The Double Prompt. This one is the worst -- I'm getting a dialogue box telling me that I'm going to get another dialogue box? Seriously? This should never happen -- ANY UAC prompt should go STRAIGHT to the secure desktop. There a user can Continue or Cancel (or be required to enter a password) and that is that. I'm glad to hear that this is an area of change for Windows 7.

    Thanks for the informative post!

  • As someone who uses Macs and Linux, the prompts are nothing new to me, I don't mind them at all.

    It's kind of like asking people to wear seatbelts. It's a pain, and slightly uncomfortable - but in the grand scheme of things it's utterly justifiable.

    What does concern me is specific flaws are being found that can escalate code to Admin privileges (a recent GDI+ flaw springs to mind).

  • I don't mind the prompts for installing software at all, my main problem is when I'm prompted for Windows operations. For example, when ever I start up my computer the first thing I do is start up task manager and I like to view all of the processes. Without UAC selecting the check box once keeps it checked for all future sessions, while with UAC I am prompted everytime I log on and check the check box. Other admin stuff like this should have an opt out of UAC prompts setting in protected admin accounts.

    My other annoyance is that when saving pictures from IE (Save picture as) the folder I saved to is not remembered throughout that instance of IE. For example if I open a bunch of tabs from my art inbox on deviantART I have to renavigate from the My Pictures folder each time I save from a different tab instead of remembering the subfolder that I save to.

  • There have been a few questions about the percentage of customers that disable UAC.  Our data is showing that about 92% of people run with UAC enabled.

    The interesting point to consider is the data about how many popups happen early in the usage of a new PC--this might cause an enthusiast to disable UAC early on and then decide not to enable it or neglect to enable it after the initial flurry of elevation requests.  That is perhaps why this number, 8% disabled, might seem a tad bit higher than expected.


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