Or there might be an alternate data source being stored within the Sage share point. Alternate data sources seen by MAS has many symptoms. Just make sure that renamed files, folders and directories no longer have a valid extension, any MAS files being stored within the share are in zip file format, are being stored outside the share point or the MAS files, folders and directories names have been butchered. (AR_Customer.m4t.old Old MAS90, MAS90backup all have the potential to still be read by MAS). I know I probably sound like a scratched LP record but you've looked into most all else
Also. Damaged pointers (embedded IO) always seems to go hand in hand with Alternate Data Sources. It wouldn't hurts to run the Embedded IO replacement script as well..