- Press COMMAND + OPTION + ESC key combination to open Task Manager.
- Select Microsoft Office App that is currently blocked from working because of the message box.
- Click End Task button at the bottom of the dialog box. Your unsaved data in the app will be lost.
- Re-open Microsoft Office App.
Option 2: Disable “Use Office 2016 to sync Office files that I open” Option in OneDrive sync client
- Click the OneDrive icon in the Menu > ellipsis > Preferences >
- Uncheck Use Office 2016 to sync Office files that I open option.
After unchecked this setting, all files will be synced by OneDrive sync client.