Hi All,

I have a VSTO Addin I created with VS2005. The Addin was installed on Windows 2003 Server with SP1 & Office 2003 with SP2.

The Addin worked for a few months. Now, when the client tries to run it he gets "Office document customization" error (see snapshot).

I got the message error by setting VSTO_SUPPRESSDISPLAYALERTS to 0.

Pressing the 'details' button gives nothing.

I tried to reinstall the Addin - didn't help

I tried to create a new public key, rebuild the project and reinstall - didn't help

When I install from the same setup program on other computers (Windows 2003, Windows XP) - it works without any problem.

All keys in registry/caspol seems OK (exactly as when I installed them).

Load Behaviour is changing from 3 to 2 (that's normail because of the problem)

What else can I check




I don't know if the client installed any programs the messed up my installation.

Re: Visual Studio Tools for Office Error loading VSTO project

Misha Shneerson - MSFT

Can you check what version of .NET frameworks is getting loaded into the process You might get an error if something is forcing .NET Fx 1.1 to be loaded instead of .NET Fx 2.0. To check what version of .NET CLR is loaded just watch the list of loaded modules and check the location of mscorwks.dll (Native debugger in VS.NET Debug->Modules is one option of how to get the list, other options are ProcessExplorer utility.)

Re: Visual Studio Tools for Office Error loading VSTO project


Hi Misha,

Since I don't hava access to the client machine, I tried to create the error in my machine (machine that has both .Net framework 1.1 & .Net framework 2).

I installed the addin and saw that everything works.

I created a file called Outlook.exe.config in my office folder with this content:

      <supportedRuntime version="v1.1.4322"/>
      <supportedRuntime version="v1.0.3705"/>

When I run outook, I get an error message but it's not the same as the one I got from the client (see snapshot)

This error has details (unlike the original error). Also, this error tells me the assembly is not available (the framework can't find the assembly) unlike the first one that finds the assembly but gives error message about his manifest.

Of course, I will check the client's computer as soon as I can.

Any ideas



Re: Visual Studio Tools for Office Error loading VSTO project

Misha Shneerson - MSFT

I double checked what are the cases when one might receive this particular error for Outlook add-ins. And there are few possibilities all related to .manifest file for this add-in:

1. VSTO can not open the manifest file

2. VSTO can not read the manifest file

Is it possible the client has accidentally deleted the manifest file.

Below cases also might show the same error but will have details available.

3. VSTO can not parse the manifest file

4. The path to the codebase in the manifest is an invalid URI

5. If you use deployment manifests - then the location of the deployment manifest is specified as incorrect URI