If you use Outlook for Windows and experience performance or access issues when using Cirrus Insight (such as a blank pop-up screen or repeated login loop), you can clear the Cirrus Insight for Outlook cache that's stored locally on your PC.
1. Close Outlook.
2. Open File Explorer from the Windows task bar or start menu.
3. Navigate to the AppData folder by following this folder path:
Local Disk (C:)
If AppData isn't visible, select View at the top and check the Hidden Items box.
4. From the AppData folder, follow this path:
Cirrus Insight for Outlook
5. Locate the CefCache folder, right click it, and select Delete.