Friday, 15 July 2011

Fix for VSTO ClickOnce application - "Unable to install this application because an application with the same identity is already installed. To install this application, either modify the manifest version for this application or uninstall the preexisting application"

If you receive the following exception even though your VSTO ClickOnce application is already uninstalled:

"Unable to install this application because an application with the same identity is already installed. To install this application, either modify the manifest version for this application or uninstall the preexisting application."


Then you may have issues with your ClickOnce application Cache. You have 2 options for clearing it:

Running the following at a Visual Studio Command Prompt:
mage -cc

OR

Running the following at a command line on any machine with the problem:
rundll32 dfshim CleanOnlineAppCache


See http://vijayvepa.wordpress.com/2011/01/11/unable-to-install-this-application-because-an-application-with-the-same-identity-is-already-installed-to-install-this-application-either-modify-the-manifest-version-for-this-application-or-uninstall/ for more details.

DDK

5 comments:

Unknown said...

David,
Your "rundll32" option for client machines is a perfect solution. It worked well for me.

Keith said...

Thank you! The rundll32 approach is the best solution since it should work on every computer.

Ravi Gupta said...

Thanks buddy, you made my day :)

Naephus said...

You saved my life today. Thank's

Jon Lewis said...

Thank you!. I uninstalled the VSTO while my addin was still running and after searching and deleting registry keys, windows still would not allow me to reinstall. After finding your solution - I was able to reinstall. Thanks!