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Updating VSTO Excel Add-In

Posted by: admin May 14, 2020 Leave a comment


I have written an VSTO Excel 2010 AddIn and successfully installed it on a machine that is not my development machine. I installed it manually by first creating a folder to hold the AddIn application files. The folder is C:\TestXL2010. I then placed all of the files from my machines project bin\release folder into the TestXL2010 folder on the test machine. Next I created and ran the installation registry script that contains the following lines.

Windows Registry Editor Version 5.00


At this point, everything appears to function as expected. Now the problem. I made some changes to the application, rebuilt the solution and copied the new set of files into the TextXL2010 folder. Excel does not appear to see the new files. It is acting as if it is still running on a cached set of the original files. I have tried uninstalling, renaming, etc. to no avail. Excel just appears to be stuck on the first version of the application. Any suggestions as to what I need to do to either clear the cached version or make Excel see the new version would be greatly appreciated.

How to&Answers:

well this could be because application is getting loaded from clickonce cache, to avoid append |vstolocal in manifestpath like “Manifest”=”file:///C:/TestXL2010/TestXL2010.vsto|vstolocal”, . vstolocal ensure that your solution is loaded from the installation folder, rather than the ClickOnce cache.


Check your system Task Manager for a background Excel.exe process running. Kill it or reboot to clear it. If an add-in fails, a copy of Excel may keep running in the background and it prevents new or changed add-ins from taking effect.