Time Machine operates while in Sleep Mode

Well, last night, about two hours after I put the Mac in sleep mode, I'm afraid I found my external Time Machine drive running again. Any other thoughts/suggestions? It doesn't makes sense to me why it would be running while it's asleep. It's not as though any files could have changed/updated during that time.

Thanks

Thanks for your continued efforts!

The SMC reset is done. (I had to also unplug my iMac for 24 hours just this past Friday. So we can probably rule that out as a factor, since the problem was occurring both before and after that reset.

Regarding the backups, I went in to Time Machine and no, actually there are no backups occurring while it's in Sleep Mode. Yet, the white light on the Seagate drive that is used exclusively for Time Machine is often on, and I can hear the drive spinning in it.

So it's pretty odd/confusing to me. Do you have any other thoughts?

Again, I appreciate your time and energies with this!

Thank you!

Thank you!

I should also add, I started this quest with contacting Seagate Support. I'm afraid they were worthless!

Again, thanks!

It's a Seagate Backup Plus Portable Drive (Model SRDOSP0). I use it with nothing other than Time Machine back ups.

Regarding anything disturbing the iMac, the only peripheral connected is my printer (which is always powered off unless I'm using it), the Seagate drive, and a dongle connecting my wireless Logitech keyboard. I use an Airport router, but that's wireless. Otherwise, nothing else is connected to the computer.

Power supply is quite stable here (I notice our locations are probably with the same utility...PG&E?) Out of an over-abundance of caution, I do have a heavy duty surge protector that the iMac runs through...just in case.

Is there anything else I can tell you, that might be helpful? I am just totally clueless as to why this keeps happening!

Thanks again!

I've honestly had this drive for so long, that I don't remember. I do know that I had to wipe the entire drive and do that multi-pass wipe to remove all traces, and then did a fresh back up of Time Machine from that point forward. I do know there is Seagate application on my Mac. But it's not active. I want to say that it also came formatted for a Mac OSX.