NM: Only mail header migrated - ! Error: Failed to save changes in MimeToMapi 0x80040109 (4312187)

Solution

This error can be caused by one or more of the following:

1.  Exchange Retention Policy.  This policy must be disabled during the migration project to prevent Exchange from throwing this error.

2. Anti-virus is active, and writing to the migrated document at the same time as CMTe.  This causes conflicts, and causes this error.

Anti-virus needs to be updated to exclude the Exchange application, as well as a number of other processes.  Read the following article regarding 

Anti-Virus Software in the Operating System on Exchange Servers: http://technet.microsoft.com/en-us/library/bb332342.aspx

3. This is a MIME issue.

Find the btmail.box file on the worker(s) and delete it.

Run the migration again.

This btmail.box file is used by CMTe for migrations. When you delete the btmail.box file, CMTe creates a new btmail.box file to replace it. It's possible the file was corrupt.

Also delete all the MAPI profiles, and create a new MAPI profile that is not in cached mode.

4. Connectivity issue with the Exchange server.  There may be issues where the Exchange server is experiencing problems, or there are intermittent outages. This can be proven if you have migrations that are successful, but then fail at a later time, or fail, but then remigrating the same data at a later time, proves successful.

Make sure your migration farm is on the same IP subnet as your Exchange server.  If migrating to O365, make sure the migration farm is in the same region as the Exchange server (data center).

The migrated data will need to be removed, and the user mailbox migrated again

If the 'Remove Migrated Data' is unable to delete the data from the Exchange mailbox, then you will need to perform an 'Advanced Find' from Outlook.

Click Tools - Instant Search - Advanced Find

Look for Any Type of Outlook Item

Click "Find Now"

Select all the migrated data

Hold down "Shift + Delete" to permanently delete items from mailbox.