To clear the Office cache on Windows 10 when the add-in is running in Microsoft Edge, you can use the Microsoft Edge DevTools. If this add-in removal doesn't work, then delete the contents of the Wef folder as noted previously for Excel, Word, and PowerPoint. ) for the add-in and then choose Remove to remove that specific add-in. To remove a sideloaded add-in from Outlook, use the steps outlined in Sideload Outlook add-ins for testing to find the add-in in the Custom add-ins section of the dialog box that lists your installed add-ins. %userprofile%\AppData\Local\Packages\Microsoft.Win32WebViewHost_cw5n1h2txyewy\AC\#!123\INetCache\ If the following folder exists, delete its contents too. %LOCALAPPDATA%\Microsoft\Office\16.0\Wef\ To remove all sideloaded add-ins from Excel, Word, and PowerPoint, delete the contents of the following folder. Manually clear the cache in Excel, Word, and PowerPoint The manual method for Excel, Word, and PowerPoint is different from Outlook. Select the checkbox Next time Office starts, clear all previously-started web add-ins cache.From the ribbon of any Office host except Outlook, navigate to File > Options > Trust Center > Trust Center Settings > Trusted Add-in Catalogs.The automatic method is not supported for Outlook.