Steps to clear local Microsoft Application Virtualization (App-V) cache file

App-V caches the applications it runs to avoid streaming them over the network repeatedly. This cache lives in the %ProgramData%\Microsoft\Application Virtualization Client\SoftGrid Client folder as the file sftfs.fsd by default. This will grow over time, so if you want to clear the cache back to blank and repopulate it, you update a registry key and reboot.
To clear it,

1. Start Registry Editor (regedit.exe).
2. Move to HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\SoftGrid\4.5\Client\AppFS (it's 4.5, even if running 4.6 of the client).
3. Double-click State and change the value to 0. Click OK.
4. Reboot the machine.