Virus message on boot after installing Mint 17 RC [SOLVED]

[runbei]

On booting after installing Mint 17 RC 64-bit in a dual boot setup with Win 7 Pro, I get a warning message about a boot-sector virus:

BootSector Write !!
VIRUS: Continue (Y/N)?

The virus warning didn't appear in Mint 16 on the same PC. It showed up immediately after I installed Mint 17 RC. It appears on a desktop PC (home-built, older AMD Phenom quad processor) but not in an identical install on a ThinkPad X201 laptop.

I found the following reference to this on another forum:

The motherboard is telling you that something wants to write to the boot sector. The boot sector is rarely written to but a virus would find it very handy to do that. An example of a valid write might be when you are installing a dual boot to Linux.

So is this a Mint 17 RC bug? Haven't found a way to turn off the message.

FOLLOWUP: A bit more research suggests this is a common issue that very often only indicates something other than a virus is trying to write to the boot sector. The solution suggested is to turn off virus checking in the BIOS, which is what I did, and Mint and Win7 boot now boot normally.

[Derek_S]

Hello runbel - If this message appeared immediately after you installed Mint 17, I imagine it's your current Windows anti-virus program complaining that there were changes made to the boot sector. And indeed there were. Which anti-virus are you currently using? If you install the free version of Malwarebytes and configure it to do a rootkit scan, it will scan the master boot record, the registry, what it refers to as startup objects, as well as the rest of your system. If it finds nothing, I would say that your other anti-virus software merely reacted to the fact that changes were made to the MBR, but did not actually find a virus in the MBR. The link to download Malwarebytes is here: https://www.malwarebytes.org/free/

First update the database from the dashboard , then go to Settings>Detection and Protection, and check the box "Scan for Rootkits". Then go back to the dashboard to start the scan.

[runbei]

Thanks, Derek. That did it. I did a Malwarebytes scan as you suggested, and it revealed no problems. Will mark the issue solved.