If you are experiencing an overlay from PS4 game dashboard stating the data is corrupted, then your PS4 is likely having an issue with reading or writing the save data.
First, check in the load screen to see if the file is detected as being corrupt by Slime Rancher. If the files do not explicitly display as being corrupted there, you can try the following:
1. Copy your save data to the PSN (PlayStation Network) or to a USB device
2. Delete the local save file on your PS4
3. Optional: Uninstall Slime Rancher (do this if you can't seem to save a new game)
4. Attempt to rebuild your PS4 database to try to resolve potential drive issues
5. Reinstall Slime Rancher and copy the save data back over to your PS4
If this does not resolve your issue, you can try reaching out to PS4's support to consider advanced options.