I was recovering my files from a internal drive which I formated by mistake. Recuva works well in scanning and recovering until this issue happen. I was recovering my files little by little from a 3TB drive of storage. I step away for a bit and when I came back to check, I can see the Recuva listed files on the taskbar preview except the program disappear when I click on it. It's still running and still have the taskbar preview. It's just won't run when I click on that taskbar preview. If I click on the program itself on the taskbar, it will open a new Recuva and the one that's stall is still there.
I don't know what cause Recuva to stop working and still show as running in task manager. I can only guess that because the hard drive I backup it to is an external hard drive. The external will stop running if there's no read or write to it. Recuva probably just have issue finding the external drive when it activate again. It's just a theory. To be clear, the drive I'm recovering is an internal storage only drive which doesn't have any system files on it. I'm restoring it to an external harddrive with USB 3.0. The external will stop/sleep when not active. Recuva stop responding probably if it or the hard drive is idle. It's just a guess.
This is the second time this same issue happen to me and it's really a pain to spend one more day to deep scan it again because the program fail to continue. You may need to think about adding save session for those who backup little by little and want to avoid program crash. I will post a request for this feature and hope you can see why it's necessary.