SAV and TimeMachine

I have an iMac with Snow Leopard. I've been a Mac user for years but I am a new user of the Home Edition for Mac. I have Time Machine in operation. I did my first Local Scan 2 days ago and it started by saying that there were almost 7 million items to scan. Fifteen hours later I stopped the scan with about 2 million items still to be scanned. At that point there were 20 threats identified, 10 on my Mac and 10 on my TM Backup disk. I did not try to remove these threats, but I ejected my TM backup volume and restarted the SAV scan, which then said it had a mere 600,000 items to scan.

It took about 90 minutes to complete and found the same 10 threats on the Mac (plus one other later on in the scan, actually). With this experience I think I can understand the logic of all this.

My question is this: As it is suggested (or that's how I read the various comments) around these forums that it is perfectly acceptable (and seemingly recommended) not to attempt or even worry about removing threats that are found on a TM backup, why bother scanning it at all?

If you ever have to recall a file from backup, SAV will nail it anyway with its On Access scanning, as I read things.

As I understand from the forums you cannot exclude things from a Local Scan, which is why (possibly in ignorance) I ejected the backup volume before my second attempt.

I think SAV is a great system though as I say I'm new to it and I'd appreciate it if someone more knowledgeable than I could comment on the above, particularly on my question "why bother scanning the TM backup at all?"

Barry

I have an iMac with Snow Leopard. I've been a Mac user for years but I am a new user of the Home Edition for Mac. I have Time Machine in operation. I did my first Local Scan 2 days ago and it started by saying that there were almost 7 million items to scan. Fifteen hours later I stopped the scan with about 2 million items still to be scanned. At that point there were 20 threats identified, 10 on my Mac and 10 on my TM Backup disk. I did not try to remove these threats, but I ejected my TM backup volume and restarted the SAV scan, which then said it had a mere 600,000 items to scan.

It took about 90 minutes to complete and found the same 10 threats on the Mac (plus one other later on in the scan, actually). With this experience I think I can understand the logic of all this.

My question is this: As it is suggested (or that's how I read the various comments) around these forums that it is perfectly acceptable (and seemingly recommended) not to attempt or even worry about removing threats that are found on a TM backup, why bother scanning it at all?

If you ever have to recall a file from backup, SAV will nail it anyway with its On Access scanning, as I read things.

As I understand from the forums you cannot exclude things from a Local Scan, which is why (possibly in ignorance) I ejected the backup volume before my second attempt.

I think SAV is a great system though as I say I'm new to it and I'd appreciate it if someone more knowledgeable than I could comment on the above, particularly on my question "why bother scanning the TM backup at all?"

Barry