Please ensure everyone apart from yourself is logged out of FactoryMaster. You then need to run finalise update. Do the following:
Click Options then click System Maintenance
Click Data Manager then click Finalise Update
You will now see a warning telling you everyone should be out of the system, if they are then click on OK
If the error message still persists, please log a new case online and reference this article. If you need assistance logging your case, please click here.