User sample deleting synth engines

I’ve had my op-z for a few weeks, now. And, so far, things have been going pretty well, but whenever I go to switch synths and leave it for too long it deletes the synth from the op-z. Is there a way to restore the engines without resetting it or avoid the problem all together?

I had that same issue. I found if I downgraded the firmware to 1.2.26 it no longer has that delete synth engine option/problem. Downgrade process is the same as upgrade.