We experienced an issue recently synchronizing a workspace. When we tried to Sync we received the following error “An Unknown error occurred while attempting to synchronize this tool, The query cannot be completed because the number of lookup columns it contains exceeds the lookup column threshold enforced by the administrator.
To resolve this issue you can do the following
- Go to Central Administration > Application Management > Manage Web Applications
- General Settings > Resource Throttling
- Increase the value in the List View Lookup Threshold
- Apply the change and test the sync again and increase the value again if need be