The "Failure to Save" error message in Planet Zoo appears when it cannot locate your default Windows 'Saved Games' folder.
Save Games should be stored in "C:\Users\%username%\Saved Games".
You can locate your 'Saved Games' folder by typing "shell:SavedGames" into your File Explorer. If nothing appears then this has been removed.
If this folder no longer exists, you can run the Restore_Saved_Games_Default_Location.bat attached to this article to restore your 'Saved Games' folder. To do this, please right-click the file and 'Save Link As', then save.
If you wish to change the location of your saved games file from the default, please right click on the newly restored 'Saved Games' folder and select the desired file path.
If you experience any further problems, please get in touch with us by using the button below.
Thanks to Shawn Brink on http://www.tenforums.com for a very informative guide that helped with this troubleshooting step.