Since when is an eSATA drive considered a 'removable' drive for backup

I've been using an eSATA drive since Win 7 and had no problem with Windows backup. Now, since Sunday morning, backup considers that drive 'removable' media and won't back up to it.

Any ideas out there?

(Since I couldn't do a Windows backup, I configured Macrim to do it, but I don't understand why Windows won't back up)

Win 7 Pro 64 bit Version 10.0.10586 Build 10586
AMD FX-8370 4.0gHz
Gigabyte FZ990-UD3
nVidia GTX 1080 FE
32G DDR3 1600 memory

None of the SATA ports are configured as hot/removable in the BIOS. However, Port 0 is not present. Port 0 is where I have the eSATA cable plugged in. Even though I have the eSATA drive powered on, the BIOS still doesn't recognize the port is active.

Windows sees the eSATA drive and says that it's on port 0 but since port 0 is not present in the BIOS, that must be the reason that backup thinks that the drive is removable. So I must have had a hardware error on the mobo sometime since the last backup and never saw the error. And apparently Macrim will do a system backup on any type of drive, so that's why that worked. I'll have to figure out how to activate the port by contacting Gigabyte.

Thanks for pointing me in the right direction.

Just for clarification, my Win 7 system has a e-sata port on a gigabyte mother board. No matter what e-sata device I've ever plugged into it, its always been removable.

That may have been the case since I started using eSATA. However, this issue just started this weekend when backup wouldn't save to a 'removable' drive (error message from backup).

Can't figure out what's changed from the previous, successful, backups.