Hi Bob,
The problem you have mentioned might not be due to cache.
Save your work and completely close Outlook.
- Press Windows + R to open the Run dialog.
- Type %localappdata%\Microsoft\Outlook and press Enter.
- Open the RoamCache folder.
- Hold Shift, select all files, then press Delete (or right-click and choose Delete).
- Confirm the deletion if prompted.
Open the Outlook again and try to edit the contacts group.
I’m eager to hear back and work together to find a solution.