When archiving a message with a OneDrive linked attachment you will get the following error in the ESM logs.
00:18:12 DEBUG: END WalkFolderPolicy() - result 0
00:18:12 DEBUG: BEGIN BLFAILEDMESSAGE::Select()
00:18:12 DEBUG: END BLFAILEDMESSAGE::Select() - result 0
00:18:12 DEBUG: calling GetProps for property 81C4001F
00:18:12 DEBUG: BEGIN WalkMessage(subject='letter',form='IPM.Note') in folder 'Inbox'
00:18:12 ERROR: Attachment has unrecognized PR_ATTACH_METHOD.
00:18:12 ERROR: Unable to get message checksums:
00:18:12 Attachment2.get_Data
00:18:12 Error 0x80004005