Ox8004060C Error Message
I cannot quite recall, however think that the problem was associated with the file size of Microsoft Outlook. I believe that when the file size is getting very close to 2GB the whole program stops receiving emails and allowing you to move or delete files. My file size was around 1.8GB
I ended up starting computer in SAFE mode (hit F8 when machine is booting up) and then opening Microsoft Outlook and commenced to delete emails.
Once I had reduced the file size a little, I accessed through the normal boot up system and I went and removed attachments (saved to my documents and relevant folder) and also all unneccessary emails.
Try this and see what happens, however I think that the file size will be the reason for the error message.
Good luck