It appears Acronis forum has replied. Here's their comments.
You needn't worry about this message. It simply states that your disk partition style will remain MBR. Such messages appear in ATIH 2012 in the disk recovery mode because ATIH 2012 supports UEFI and GPT partition style. When a PC uses BIOS, the partition style remains MBR. If you've tried to restore this backup to a UEFI-booted PC using Universal Restore, the disk partition style would be converted (migrated) from MBR to GPT.
So, in this case, just shot the messager.