I tried your suggestion and it seems to work (partly). It did compact (no error message). In the window where you can increase disk space or reclaim, it says 47GB now (0,5GB more than the actual data size). But in the folder view it's still wrong. With 47GB of data, the disk area still is 469GB. I've restarted Espionage3 and I've restated the MacBook Pro. It's still wrong in the folder view, buts it seems to be correct when you go into the "Adjust Folder Size" area.