The error code CE-34878-0 is often connected with file corruption issues on your PS4/PS5 - it may indicate a damaged PlayStation operating system or game install. Commonly suggested fixes include:
- Restarting the console
- Make sure your PlayStation system software is fully up-to-date
- Try reinstalling the game if you're experiencing this error only in one particular game
You may also wish to try re-initializing your console's operating system. You can do this by going to Settings -> Initialization, however, we do not suggest doing this unless the other suggestions don't help.