Migration log contains a 'Truncated long subject to first 4096 characters' warning message.
Migrator for Notes to Exchange (NFNE) environment details:
MFNE: 184.108.40.206 Windows Server 2008 R2 64 bits English - 1 vCPU and 4 GB RAM.
SQL: SQL 2008 R2 Windows Server 2008 R2 VM 1 vCPU and 4 GB RAM.
Exchange: Exchange 2013 CU7 Windows Server 2012 R2 Standard 4 vCPU and 64 GB RAM.
Domino Lotus Client: 8.5.3
The verbose wlogz file contains the following warning message:
Line 525983: 17:43:26 WARNING: [4685-33-259-00000000]Truncated long subject to first 4096 characters
On Page 46 of the MFNE Pre-migration Planning Guide under the 'Other Data Migration Wizard issues' section, there is further information regarding this warning message:
Message subjects truncated: Messages with subjects longer than 4096 characters cause MNE to stop processing a mailbox at that message. MNE therefore truncates longer subjects to 4096 characters.
Meanwhile, Outlook truncates any message subject longer than 255 characters to 255 characters. A message subject longer than 4096 characters will be truncated twice during migration: once by MNE, to 4096 characters, and then again by Outlook, to 255 characters.
This is just a warning message that the subject line was too long and was therefore truncated. The migration then continues as normal.