E2K7 Migrating Mailbox to E2K13 and move back to E2K7

I found only one post where someone was having an issue moving an E2K7 mailbox back from an E2K13 move

My Migration log has the following as to why the mailbox will not move back to E2K7:

2015-04-20T15:56:57.348Z,41,New-MigrationBatch,Information,",,",Creating a new attachment with name Errors.csv
2015-04-20T15:56:57.535Z,41,New-MigrationBatch,Information,",,",Saved attachment with id EABHtR0Afgf4RL7kRG3HZUp9

I have searched for both errors.csv and the saved attachment with the avoe ID and I cannot find these files.

Can someone please help me out.

many thanks