Tone's Notes

Managed Add-Ins built with Visual Studio .NET use the DLL mscoree.dll to load.

Microsoft is aware of a problem affecting some developers where the add-in works fine when built and installed by an add-in setup project, but fails to load when recompiled by the IDE. What drives this behavior is a registry key value that is written with a full path by the installer but without a path by the IDE’s build process.

Every add-in class has to have a GUID registered under HKCR\CLSID in the registry. The registration includes an “InprocServer32” key which points to the mscoree.dll.

If the value includes a full path, the add-in always loads (all other issues aside). If the value is just “mscoree.dll”, the add-in only works for some people. It is not known at this time by Microsoft what configuration differences cause this behavior.

When you get tired of the build, install, run manually, attach debugger cycle, which does work reliably, and wish you could just press F5 and hit your breakpoint, do the following:

-         Add a new text file to your solution with the name “FixMscoree.vbs”.

-         Edit the following into the file, replacing the guid with the one your add-in uses:

' Run with project build event: cscript $(SolutionDir)FixMscoree.vbs

Dim wshShell,wshEnv,sPath

Set wshShell = CreateObject("Wscript.Shell")

set wshEnv = wshShell.Environment("process")

sPath = wshEnv("SYSTEMROOT")

sPath = sPath & "\System32\mscoree.dll"

'guid is of the form {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}

wshShell.RegWrite "HKCR\CLSID\{77C3AFCA-8AF6-4b7f-8D7C-657CDB17856E}\InprocServer32\", sPath, "REG_SZ"

Set wshEnv = Nothing

Set wshShell = Nothing

-         Set ProjectàPropertiesàBuild EventsàPost-build Event Command Line to “cscript $(SolutionDir)FixMscoree.vbs”

To the best of my knowledge there are no relevant knowledgebase articles on this problem yet. If you know of one, please post or send the reference.