Can you copy a file with a data bomb (not accessing it) without setting it off?

I believe the answer is yes. This was something they explicitly changed in 5th ed but for 4th ed, you could download it without setting off the bomb. The key is the wording; accessed. If you take that to mean opened, then it won't detonate until you do that. If you take it to mean interacted with, then it will unfortunately detonate the second you interact with it somehow beyond making a perception test or using the defuse program on it.

In 4th Edition: Why data bomb the file when you can data bomb the node access point. Double fun if you do both.

Indeed. Though this always struck me as an odd thing to do since a hacker could just deliberately set the thing off and crash your node. I suppose if the server was just back up storage or something, that would make sense but an active node? No, too easy to cause a crash. Also pretty easy to spot since most hackers will (or at least they bloody well should if they know what they are doing) do a matrix perception test before entering a node and (again assuming they know what they are doing) ask if such a thing is on the node. Some times, when going after a file, they forget to ask in the rush of getting the goods.

Add a "Pavlov" option and the data bomb now doesn't crash when it detonates. Add psychotropic on top of that and now you've got a black hole (hope you remembered to load your biofeedback filter). A mere rating 4 data bomb can have both.

I tend to steer clear of psychotropic effects. No real rules on removing the effects (GM fiat) means you have a good chance of inflicting negative qualities for a failure to make a perception test or a disarm test. A little heavy handed in my opinion.

But you can skip side effects entirely and just add the additional biofeedback damage to really brain fry the speed hacker that forgets to run a biofeedback filter program. And that's on top of the dumpshock if the matrix damage is enough to crash the invading commlink.

Yes Indeed... And that Black Hole does not have to damage the hardware itself, just the intruding Hacker (the persona). Damaging the hardware/software is optional, not a requirement.

Did that. Databomb rating 6, Pavlov option, Biofeedback option. Hurts. I excluded the psychotropic option because that is a tad bit evil. Hm, maybe I'll go back and buy an extra program with that option... my character has trust issues and is a trapmaker.
Be very careful, though: A databomb with a high rating might very easily kill any technomancer foolish enough to set it off.

As to the initial question: I'm not certain on the exact wording of the rules, but we always played "accessing it" as "interacting with it any further than a mere scan".

Even Decent rating Data Bombs can eliminate a Technomancer with relative ease if it rolls well enough.

Yes, same with us... "Interacting beyond a scan" is how we ran it as well... Means you cannot just copy it and move along.