I have got a new laptop (an Apple MacBook Air 11″) and after installing BootCamp, Windows 7, VB6, VS 2005, 2008 and 2010, yesterday I noticed that when loading MZ-Tools 3.0 for VB6, it prompted to repair Visual Studio 2010. I had received the same or similar issue from 2 or 3 users these last years that I never knew how to solve, so I could only recommend to repair or reinstall Office, VB6 ,etc. Today I have investigated more and it seems that there are multiple causes but one of them documented by Heath Stewart was certainly my case:
How to work around the issue when opening Office applications repairs Visual Studio
http://blogs.msdn.com/b/heaths/archive/2009/05/29/how-to-workaround-the-issue-when-opening-office-applications-repairs-visual-studio.aspx
That is, if there was an external drive connected when you installed Visual Studio, you get the issue when you load some Office application, or some application using VB/VBA. Of course this issue doesn’t happen if you install from the DVD, because the drive (typically D:) will be there always, but it happens if you have an external drive connected, specially if that is the drive where you are installing from!. It happened that other times I copied the setups to the internal hard drive before installing Visual Studio, but since the MacBook Air has only 128 GB of internal hard drive, I installed from an external drive.
That said, the workaround proposed in the post didn’t work for me. I guess that using the variable %ProgramFiles% on my Windows 7 64-bit rather than %ProgramFiles(x86)% didn’t help. Anyway, I got it so messed that finally I had to uninstall completely VS 2005, 2008 and 2010, which is a horrible experience because you have to uninstall lots and lots of separate setups (Visual Studio is by far the worst product regarding uninstallation). Then I started again the installations, but this time copying the media to the internal hard disk (it is a good thing to have USB 3.0 technology). And now I have 27 updates to install from Windows Update, but the issue is solved.
I hope this help others, and myself in the future 😉