When I double-click on the Subnautica pic to launch the trainer, it loads and then unloads, loads and unloads, repeat, rinse, repeat. If you open up the task manager, you can see it appearing and then disappearing as it cycles.
Delete the trainer and re download and use the clean trainer temp files in the TM and try again.
Trainer settings for infinite cyclops health do not work. Seems identical to a problem reported back in 2019 by another user. Slightest scratch triggers full cyclops destruction and "abandon ship" scenario.
I tried a few settings (everything launched as admin, alt-tabbing, etc.) to see if I could figure out what exact option was causing this. With just the trainer on (no options selected), the problem doesn't appear. With ONLY the infinite cyclops health triggered, the cyclops isn't destroyed, but continues to take damage. Inside the cyclops, the interface reports 100% health, but the ship leaks and has damage outside that you have to go repair.
I then put all the other trainer options on, and got hit once by a creature, triggering full explosion. So it seems (1) the infinite cyclops health doesn't work, and (2) some other option is causing the cyclops destruction.
Possible solution: I was having this same problem with both Cyclops and Seamoth and tried all the suggestions. Then I ran the trainer without any options activated and no hull breach or destruction. I then activated the trainer and activated the infinite health for both separately and had no destruction or damage. I then began activating the other options separately. As soon as I activated Super Damage and hit the sea floor my vehicle was immediately destroyed.
I used the trainer before for while and did not have this problem. It was only after activating Super Damage that it began happening.
It seems the issue may be with the Super Damage option and not the Infinite Health options.