How to clear cache in Outlook to troubleshoot Web Add-ins

Problem:

You need to clear cache in Outlook for Windows to troubleshoot issues with the CodeTwo Outlook add-in (or any other Web Add-in). For example:

• The add-in works in Outlook on the web but doesn't appear in the classic Outlook for Windows.
• The add-in doesn't automatically add signatures to emails.

Solution:

Follow these steps to clear the Outlook cache in Windows: 

1. Open the classic Outlook for Windows and go to File > Options > Advanced.
2. Check if the Show Apps in Outlook option is enabled (see Fig. 1.).
   • If enabled: go to

     %userprofile%\AppData\Local\Microsoft\Outlook\HubAppFileCache

     and delete all contents of this folder.
   • If disabled: go to

     %localappdata%\Microsoft\Office\16.0\Wef

     and delete all contents of this folder.

Fig. 1. The Show Apps in Outlook option (enabled) in the classic Outlook for Windows.

3. Restart Outlook.

You can now verify if the CodeTwo Outlook add-in works as expected. If not, try performing the steps outlined in this section.

If you're looking for instructions on how to clear the cache in other versions of Outlook, refer to the following Microsoft articles:

• new Outlook for Windows
• Outlook for Mac
• Outlook for iOS

Completely reinstall Office apps (Microsoft 365 Apps) in Windows

This solution is recommended by Microsoft if clearing the cache didn't resolve the issue with the classic Outlook.

1. Open Control Panel (press Windows Key + R, type control, and press Enter).
2. Go to Programs > Programs and Features, then uninstall your Office suite (Microsoft 365 Apps).
3. Open Registy Editor (press Windows Key + R, type regedit, and press Enter) and delete the Office folder from the following paths:

   Computer\HKEY_CURRENT_USER\SOFTWARE\Microsoft
   Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft

4. Open File Explorer and delete the Office and Outlook folders from these locations:

   %appdata%\Microsoft
   %localappdata%\Microsoft

5. Download and install the Office apps (Microsoft 365 > Apps).
6. Open Outlook and configure your Outlook profile.