Welcome to the forum! I edited the title of your post a bit to make it easier to find for others. Hope you don’t mind.
As I understand the issue is that the node stops generating new files in the store folder after backing it up. This is probably an issue with your backup procedure.
You can find generic information about backups/node migration here:
And there are a few guides out there with detailed instructions on how to create backups:
Let me know if this doesn’t resolve your problem please!