2
votes

I just installed Visual Studio 2012 Ultimate and I am trying to create a managed code extension project for Excel 2010 (32 bit Office Professional Plus). I have tried using the .NET 4.0 template contained in VS Ultimate for an Excel 2010 workbook. When I create the project everything looks fine until I run it.

Excel opens and I get the error message "The customization assembly could not be found or could not be loaded. You can still edit and save the document. Contact your administrator or the author of this document for further assistance." The details section is blank.

I have tried everything I could think of to figure this out and I have run out of ideas. I removed all addins from Excel except for the VSTO Design-Time Adaptor for Excel. I removed all personal macros. I set every directory I could think of to "trusted" in Excel and lowered the security settings for all options to "enabled (not recommended)". I completely uninstalled Visual Studio and re-installed. There are no errors or warnings showing up in Visual Studio. I also checked to make sure ".NET Programmability Support" was installed for my copy of Microsoft Excel.

I would link my code but I haven't written anything. I can't even get the default template to load when I run the project. A few others at work have the same setup as me and VSTO runs fine for them using the same steps. I even had someone send me a working project but it gives me the same message when I try to run it.

Is there anything else I can check to see where the problem is occurring? I tried setting break points in the project but it is failing before it gets to any of them.

Thanks so much for your help.

2

2 Answers

0
votes

I've run into the same problem with Visual Studio 2010.

I isolated the problem to an SSRS reporting link we were trying to run from the add-in. I removed all the reporting stuff (service reference, sub-dirs, etc.) - the add-in runs fine.

0
votes

We just ran into this and discovered that a method had a system exception that was not handled. It was hard to track down but once the culprit method had an exception handler the customization finished loading properly.