Eagle prompted 'Library is missing' when using cloud sync tools

As we have mentioned in the very beginning, Eagle is a desktop-based App, the database (Library) must be existent in the local drive so Eagle is able to identify, display respective items. If you encounter issues like Cannot find Library, data async, broken thumbnails and etc, the issue might be related to syncing setups. In these case, please follow the troubleshooting steps: 

• Force Reload Library
  Click the Library's name on top-left, Select 'Force Reload' option from the menu, This will ensure the data read by Eagle is up-to-date:
  

• Make sure the Cloud-Sync client is in sync/up-to-date 
  There is a chance that the file you are viewing or opening wasn't uploaded/downloaded completely, hence resulting in the display issues. Please make sure that files are synced successfully. You may open the Cloud-Sync Client on both your devices and check the progress log to make sure that file sync was processed successfully, the syncing speed may vary depending on the network environment.
  
• Please also make sure that the essential file for Eagle Libary  (OOO.library/metadata.json) is synced properly and error-free (e.g. 0kb file)
• Disable 'Files on Demand', 'Optimize Mac Storage' or options alike
  When these options are enabled, files will be uploaded to the Cloud-Sync server, whereas, files in your local device will be replaced with a shortcut. This helps saving up drive spaces, however, files in this form cannot be read by Eagle. If you encounter similar issues, please refer to our articles respective to each service: OneDrive, iCloud, Dropbox
• Reboot Cloud-Sync Clients
  It is also possible that the client didn't show the sync update status correctly, in this case, you can reboot the client to force it to check/detect the sync process again.