Event ID - 8501

Event Id8501
DescriptionUnable to move mailbox <mailbox name>. A problem occurred while opening an attachment. Parent folder name: <folder name>, parent message subject: <subject>; Error code: <error code>. Run ISINTEG to check for any problem in the database "<name>".
Event InformationAccording to Microsoft:
This behavior can occur if the antivirus software that is installed on the computer is scanning the database while the move mailbox operation is being attempted.
To resolve this behavior, disable the antivirus software and restart the computer. If this step does not resolve the behavior, remove the antivirus software completely, and then restart the computer. When the mailboxes have been moved, the antivirus software can be re-enabled or reinstalled.

This information from some newsgroups may help you:
Stop the Information Store service. Contact Microsoft Product Support Services for assistance running the Isinteg utility to check and repair any private or public information store database inconsistencies that may have occurred.
Reference LinksXADM: The Move Mailbox Operation May Be Unsuccessful and an Error Message May Be Displayed When Antivirus Software Is Installed

Catch threats immediately

We work side-by-side with you to rapidly detect cyberthreats
and thwart attacks before they cause damage.

See what we caught

Did this information help you to resolve the problem?

Yes: My problem was resolved.
No: The information was not helpful / Partially helpful.