no, I get the message: Cannot move the items. The folder is full.

Have you emptied the Deleted Items folder?

You might need to scan the PST file for corruption. See if this helps: http://www.officeforlawyers.com/outl...ol.htm#SCANPST

Does this happen even if you start Outlook in Safe Mode? (hold down CTRL while you click the icon) See if this helps: http://www.officeforlawyers.com/outlook/tsol.htm#safe

Yes, I have emptied the deleted items folder many times.

I have exited Outlook and saved a backup. Weird: mailbox.pst is 1.81 GB, mailbox.backup.pst is 864 MB.

I then started Outlook by <Ctrl> clicking the icon in the task bar, nothing shows that I am safe mode, should it? I now managed to delete two folders and move another folder, but then everything went back to "folder is full".

How can I see which version of .pst file I have?
How can I see I am in safe mode?
Can I simply rename the backup file and start with that one as the mailbox file?

Haven't tried repairing the .pst file yet, find it a bit tricky