User Account Control (UAC) can seem mysterious. After all, if I’m a member of the Administrators group, shouldn’t I have access to everything? If you’re a developer, you’ll run into a UAC issue sooner or later. In this post, I’ll cover the basics that every developer should...

If you increase your DPI setting in Windows 7 (or Vista), you may notice your application doesn’t look the way you intended. What’s the Big Deal? You may say, “Nobody changes the default DPI, right?” Well, Windows 7 might. Windows 7 may increase the default DPI setting based on the resolution the...

If you run notepad elevated (Right click | Run as Administrator), and you try and drag-and-drop a file from Windows Explorer, nothing happens. It looks like it is going to work because the pointer icon changes but the file doesn’t open. Weird, huh? What’s Going On? In the traditional NT Security...

There are some very common application installer issues developers run into due to UAC .  Most of the issues are easy to fix.  I’ll cover the most common issues in this post. Per Machine Installers Need Admin Privileges Unless you have a ClickOnce installer, your installer probably installs...

When a new OS is released, a high percentage of applications don’t install or don’t run because they check for a specific OS version. The application or installer checks for a specific version number and exits if it isn’t what is expected. I’ve heard claims of up to 50% of incompatibility...

In most cases, 32-bit applications execute with no issues on 64-bit thanks to WOW64 . However, there are a few cases that you may need to make modifications to your application in order for it to work on 64-bit. I’ll cover the common issues and possible solutions in this post. 64-bit OS Basics...

We had a customer in the lab recently and they were quite certain their application was Windows 7 ready. To their surprise, it had several issues in certain situations.  In this post, I’ll talk about one of the situations they encountered as well as other stumbling blocks you might run into with...

Recently, someone asked me this question in e-mail -- “How do I get my application to run elevated when someone launches it?” Instinctively, I responded with a “You need to manifest it.” I got a nice long e-mail in return. ;-) I quickly realized that application manifests appear simple but are quite...

If you have an existing application, you may be wondering if it’s going to work on Windows 7.  If it works on Vista, you have a good shot at it working on Windows 7. As a developer or a tester, you may be wondering if you have tested your application to uncover potential issues on the new OS. We...

I had written a draft of this post a while ago (last year).  I use Live Writer as my blog editor.  Between Live Writer and Intellimirror ,this draft has survived multiple reloads of interim builds of Windows 7.  So, I think in some ways, it deserves to be resurrected and posted. :-) ...

I know I could talk all day about application compatibility topics and not cover everything that can be discussed. Here’s a one hour webcast I did that focuses on the top issues and most confusing topics for Application Compatibility. I do some of my favorite demos showing UAC architecture, data redirection...

If you use the ATL Server performance counter libraries, you may run into a problem on Vista and WS08. The ATL libraries don't play well with the updates to Windows Resource Protection. WRP enforces restrictions on the registry to prevent corruption of performance counters. ATL breaks these rules and...

When you work on a given subject for a while, you tend to jump right in and forget to start at the beginning. In the Application Compatibility lab, we kick off the week with an overview presentation and cover the basics of common compatibility issues. Those topics are probably a good place to start with...