I have upgraded my PS4 to a PS4 slim and I have the drive with all of the games and saved in it. When I tried to just switch the HDD of the slim to the HDD from my old console, it wouldn't work and was asking for a USB drive with a update or reinstall file. I have replaced and reinstalled multiple PlayStation drives and decided to just update but that did not work.
And yes I know im an idiot for not backing up everything and assuming with my big IT ego it would be easy (also the person I sold my PS4 to has already taken it apart for spare parts so that is out the question)
Best Answer
Unfortunately you are out of luck. The content on the drive is locked to the console it was used on, so moving the drive to a new console means it must be formatted before it can be used. If you put the drive back into the original console then it would continue to work (but I see that you no longer have access to the previous console).
The only option you have is to format the drive on the new console (and lose all the data on the drive as a result). You would then need to download your games again, and your save data (if you have PS+).