To make a long story short, I bought a new hard drive for my PS4 (HGST 1.5TB) so I didn't have to mess around with transferring a bunch of data later on. However, I already had a couple games installed, KZ: Shadow Fall and Resogun. I'm not worried about Shadow Fall, since it's a hard copy, but Resogun has me a little worried. What happened was, I got the new hard drive, and it was hard locking my PS4 to where I had to manually power it down completely. This happened 4 times in the first hour, but it was after I downloaded Resogun. This means that it has been on 2 hard drives now. I am sending the new hard drive back for a replacement of the same drive just to see if it was defective, which it probably was, since people, overall, have been having good luck with this drive, but I'm worried because this means that Resogun will have been on 3 drives. So my question is, "How many drives can a game be on before DRM becomes a problem?" I hadn't even thought about this until today when I got my replacement drive, and now I'm a little worried that, if this drive gives me trouble too and I have to replace it again, I'll eventually not be able to install the game because of DRM issues not allowing me to install it on another drive. Anyone have a definitive answer as to how many drives a game can be installed on?

@tyrrael I'm pretty sure you can install a game on as many HDDs as you want. The DRM is in it being tied to your PlayStation account which is registered to one device at a time.

Even if you handed a HDD with Resogun installed on it to someone else, they likely couldn't play it without you being bumped out of being able to play it on the other HDD.

In the downloaded game user agreement, it mentions:

One-time license fee for play on purchasing account’s designated, primary PS4™ system and other PS4™ systems when signed in with purchasing account.

So, you can play it on your primary PS4, plus on other PS4 systems as long as you are signed into them. There doesn't appear to be a limit on how many times you can do that, and thus, that should cover switching HDDs as well.

@truthtellah: Well that's a relief, mostly...I don't know if you know, but if I activate my PS4 as my primary, will I have to deactivate it before I change the hard drive? I deactivated it before I switched them just to be safe, but I never activated my PS3 either, as I am the only one who uses it.

@tyrrael: I don't know, but that seems like a prudent thing to do just to avoid any possible confusion.