When an active sync is underway, if you click Pause and then restart the Creative Cloud desktop application or your computer, the Files panel goes blank and shows a continuously spinning progress wheel.
Solution
Try the solutions below to troubleshoot the issue.
Solution 1
Hold down the Ctrl key while pressing the 'Quit' button under Preferences. This step kills all the CCDA-related processes together such as Creative Cloud Core Service, Adobe Content Synchronizer, etc.
Solution 2
Uninstall the Creative Cloud desktop app using the uninstaller available at https://helpx.adobe.com/creative-cloud/help/uninstall-creative-cloud-desktop-app.html, and then reinstall.
No restart of Windows or MAC is required.