NM: Migration Errors - Error: Extracting message attachment 'C:\Windows\TEMP\Attachment\Coal Inve (4312237)

Issue

I'm receiving the following error messages in my migration log.  What is the cause?

!  Error: Extracting message attachment 'C:\Windows\TEMP\Attachment\Coal Inventory Report Draft 081210.doc' - Entry not found in index Decryption was unsuccessful.  The message still contains encrypted items. Message migrated WITHOUT the encrypted items.
(subject: Time Sheet WE 8/15/10)
(folder: Inbox)
(Notes MessageID: <OFB217C556.446CC8AA-ON8625777E.005C5BCF-8625777E.005C69FC@LocalDomain>)
Decryption was unsuccessful.  The message still contains encrypted items. Message migrated WITHOUT the encrypted items.
(subject: customer aging report)

Cause

As you look through the log you will see the user's content was not decrypted before trying to migrate the user.  Notes Migrator (CMTe) can see the attachment, but cannot gain access to it, due to the encryption security

Solution

Send the user the decryption button via Notes Migrator notifications.
Remove the migrated data from the destination mailbox
Clear the migration history
Run the migration once the decrypt process is completed.