Boot virus detected on partial disk image, false positive?

Avast Free detected WXY-B boot virus on a Macrium Reflect image file of mine. I suspect a false positive though.
I gather WXY-B infects the mbr and the 1st partition boot sector, but there was no 1st partition in my image. It wasn’t a full disk image: it had just the disk’s mbr and two final partitions, including an unformatted partition. See screenshot below, the imaged partitions are on the far right hand side.

https://forum.avast.com/index.php?action=dlattach;topic=170185.0;attach=161240;image

Besides, other Reflect images I created on the very same day, containing the same disk mbr but some other partitions on it, were NOT detected as infected with WXY-B.

have you tested file at www.virustotal.com ? … if tested before, click rescan for a fresh result
post link to scan result here

It’s a disk image file sized over 1 GB, so I cannot upload it to VirusTotal.

report it here https://support.avast.com → avast virus lab and you will get instructions how to send it to the lab so they can check it

Done, thanks!

Avast Virus team examined my disk image file and confirmed it is safe, no boot virus, just like I thought. :slight_smile: