I recently encountered a bug I hope the developers are going to resolve soon when I opened the mesozoic era (done a million times) and my game straight up reset (530h lost). I looked up on the internet but nothing seemed to help. Here's what worked for me:
-Go to Android>data>com.computerlunch.evolution>files (you might have to open it with a specific app, Files should work)
-Important: do this ONLY if you can see the .restore files have the same creation time of the non .restore files because it means they are all already corrupt, hence useless (this was my case).
Move out of the folder these files:
savedGames
savedGames.restore
savedGames2
savedGames2.restore
savedGamesDeepBackup
ATTENTION! The Data folder and its subfolders are protected by andorid. Once you delete or move a file out of it you won't be able to put it back in without pain and suffering (I won't explain it here).
-You will see a bunch of savedGames_Backup files. Find the most recent one but previous to the reset by checking the date and time of creation, not its number. For me it was savedGames_Backup_2.
-Rename the file like this:
savedGames_Backup_2>savedGames (if there is .gd at the end, keep it: savedGames.gd)
-Launch the game
-The game could tell you there is a conflict between local saves and cloud saves: choose to UPLOAD your LOCAL saves TO the cloud (otherwise you'll download again your corrupt files).
-Enjoy.
If no other solution works, I hope this can help someone.