NM: Migration problems - ! Error: Unable to open MIME database cache btmail.box - File does not e (4313529)

Issue

We are getting the following error in the migration log.  Even though we can see this ntf file in the data directory and this is a single user Notes install, and all applications are US versions.

Initializing IBM Lotus Notes
Notes workstation version: Release 8.5.3|September 15, 2011
HEARTBEAT interval set to: 10000 ms
Processing bodies as MIME.
Creating BTMail.box cache for MIME processing
Unable to locate mailbox.ntf. Attempting to create cache from mail7.ntf
! Error: Unable to open MIME database cache btmail.box - File does not exist
! Error: Unable to initialize source platform IBM Lotus Notes.

Solution

There is some sort of corruption with your Notes install.  We have found that copying the 'btmail.box' file from the Migration Control Center(MCC) and replacing the Data directory on the migration worker(s) resolves the issue.
Or you can create a new btmail.box from the Lotus Notes create new database menu.