MBR Check version 1.2.3 Resulsts on USB drives

I ran MBR Check and have a question about the results.

Drives 0 and 1 are Internal Seagate 1.5TB drives, their MBR tested ok. Drive 0 has 2 partitions on it (C: and E: ) and Drive 1 is partitioned as D:

Drives 2 and 3 are External Seagate GoFlex 2TB USB drives and both of their MBR Checks were listed as "Unknown MBR Code". Drive 2 is partitioned as L: and Drive 3 is partitioned as V:

Is this normal for external USB drives?

I selected option 3 and exited MBR Check because I didn't want to risk messing up my USB drives since they have all my backups on them.

I ran a full antivirus scan with Avast Internet Security 2012 (purchased) and scanned with Malwarebytes (purchased) and both came up clean.

Thank you for any help or opinions.

 

No, I'm not having any malware or virus symptoms, Windows 7 is working great. I read about MBR Check on MajorGeeks and decided to give it a try.

The external USB drives have never been used on another computer and I have never had malware or a virus. I was just curious about the "Unknown MBR Code". I really wasn't worried about being infected since both internal drives tested ok.

About an hour after posting my original message last night, I thought those drives may be connected to my external USB hub which might have been the cause. But I traced the wires and they are connected directly to the USB ports on the back of the computer.

Thank you very much for your reply. I am sure you are right and that it is a proprietary/special MBR that is not known to MBRcheck.

Thank you,
Dan