David (NordaHL)Creator of this doc Document Updated agoYou can't back up? Even when you click on peristence:? And so, after the reboot it all goes away? It is a problem of technical administration and not coming from my scripts. To solve this problem of permission, contact your technical administrator. And ask for permission to write in the data folder. Folder generally used: \Steam\steamapps\common\GarrysMod\garrysmod\data 💡 I am not your technical administrator so I'm not suppose to know your system. But his information has always solved this problem.
You now know the source of the problem. If you do not have administrator who manages the technical part of your server, these links are from my own research, they are reliable and can answer your needs: Solution for Windows Server Solution for Linux
If this does not apply to you then a simple Google search with these key words might help you: +Permission +Right +Folder +The name of your operating system