Lex III: Actioni contrariam semper et æqualem esse reactionem: sive corporum duorum actiones in se mutuo semper esse æquales et in partes contrarias dirigi. I remember a time when all bugs were bad, and it was my job to find and destroy them all. That, of course, was when I was a developer. My perspective...

I wanted to document a bit of detail about managing the Program Compatibility Assistant, a bit of technology we added for Windows Vista and have been enhancing since that time – I figured it was probably time that we came out with an update for Windows 7. What motivated this was a series of...

I wanted to post a response to what I consider to be somewhat suboptimal advice, with the hopes of correcting it. In recorded history, there have been a number of classic blunders when it comes to advice. They include: “ Hey, let’s start a land war in Asia! ” “ I really think you should buy the Betamax...

This post corrects an error from a previous post. Back when I was explaining the changes in the operating system layers for Windows 7 , I incorrectly described the AdditiveRunAsHighest. Since RunAsHighest is already confusing enough, and AdditiveRunAsHighest is even more confusing (even I got it wrong...

A little while back, those of us who explain application compatibility for a living and try to help people get their arms around it ran up against those who implement it in the product on the scale of … the whole earth. Those of us who explain things for a living really prefer (really, really prefer...

I have had the Stock Viewer Shim Demo application available for over a year now, and I'm delighted at how much impact it has had. I see people using this all the time! But previously it was available only in English. Well, no more - it has now been (mostly) localized to Japanese! Enjoy.

I have an ongoing conversation with a customer whose application is now popping up a Program Compatibility Assistant dialog box, where it didn’t used to before (on either Windows Vista or Windows 7 beta). What’s going on? Well, when I cracked the resources for the binary, you can spot right away that...

ComputerWorld did a story on shims featuring my session from TechEd North America – check it out: http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9133382

Those of you who write application installers using Windows Installer may have noticed a bit of a change in the behavior of version checking in Windows 7 – if you happen to be doing your version checking from a custom action. Let’s have a look. If you’d like to follow along, here’s what you need to do...

It’s visible in the beta, but I haven’t heard a lot of people talking about this externally. Regardless, I wanted to shed some light on what happened, and add a bit of the human perspective behind the decision. If you inspect the operating system layers (called Compatibility Modes in Compatibility Administrator...

I’m still catching up with requests to talk about stuff – here’s one that came in back in June (and just came again today from somebody else): “MoveIniToRegistry clearly requires parameters, but there's no documentation defining what these are.  (Presumably this fix will apply an IniFileMapping...

The same question came up two times in 26 minutes (on the same discussion list, no less), so I figured I’d answer it once here as that seems a reasonable indicator that others may have the same question. What is the deal with shimming on Windows Vista 64-bit? Well, it turns out it’s a bit of a mixed...

A question came up via comments. (I was going to say that it came up recently, but another glance reveals that it came up in, oh, June. I don’t think I can fairly call that recent…) “…the fix seems only to work if the directory structure exists…” This is true, and worth noting. If you point the fix to...

When you come across issues debugging applications, there are typically several ways to solve them. Today, I'm going to pick on our own stuff and throw a few different shims at it. Interestingly enough, what I'm going to be shimming up will be the tool I use to create shims: Compatibility Administrator...

I had a comment come up on an earlier post : "FYI, I've hit a limitation with CorrectFilePaths - the maximum amount of data that can be entered in the parameter field is 512 bytes - not enough to fix more than 2 files under "Program Files" unfortunately..." Now, I knew the limitation existed, but I had...

I send out a lot of links to my articles in response to questions that come up, but the other day I had a chance to use a pile of them to solve a fairly complicated problem end to end. So, I figured I'd share how we can piece together all of this knowledge to solve a more sophisticated problem. Let's...

Last week, we updated the documentation for the Application Compatibility Toolkit. It's kind of hidden, though - if you go to the Application Compatibility Toolkit download page , you will find a new item in the list of files: ACT50_Doc_Update_Installation_Instructions.zip (1.9 MB) It's got a bit of...

Every now and again, I bump up against a setup application (it's almost always a setup application) that tries to drop older versions of protected operating system files. It's fairly easy to mitigate, but I thought I would go through some of the mechanics, and some of the places where the mitigation...

I received a request to talk about a particular shim. And yes, I received that request over a month ago, so ... sorry about that. Nonetheless, I've managed to scratch out a little niche of time to discuss the shim: OpenDirectoryAcl Yep, this does exactly what you would expect it does, modifying the ACL...

A question came up today: Are any event logs produced when you run an application with applied shims? I've tried different variations of shims trying to get the desired results with no luck. It's probably UE, but I can't tell if the shims are erroring out because the syntex is incorrect, the file location...

A comment came up on a recent posting regarding modules, inquiring about processes. Specifically: Do these included/excluded modules have to be in the same process, or can they include other processes too? (I have an application that calls multiple child applications that all need to be shimed in the...

I received one comment on my recent blog post on copying from the system shim database, which I think is worthy of discussion as I have heard similar questions before: I have found previously (under Windows XP, haven't attempted under Vista) that some of the built-in shims weren't suitable. I had a custom...

I hear about a bug now and again with Compatibility Administrator [CompatAdmin]. It always surprises me when I hear about the bug, because you can only hit it if you are trying to do something that there is no point in doing (which is why we never caught it before). Here's how you reproduce the bug....

A question came up in the comments of one of my posts, and I think the answer is important enough to elevate to more than just another comment (and I didn't even answer completely in that quick response). When you are configuring a shim and press the "Parameters" button, we've talked about the "Command...

When talking about application compatibility and mitigations, virtualization is almost always mentioned as part of the discussions. This could be machine virtualization or application virtualization . And, to tell you the truth, the application virtualization part is one that I, and many others, are...