Restores your old files and ends the updating
If you're not sure, check out this info: Our backups restore your account to the state it was when we restored it, i.e.
In System Restore, the user may create a new restore point manually (as opposed to the system creating one automatically), roll back to an existing restore point, or change the System Restore configuration. Old restore points are discarded in order to keep the volume's usage within the specified amount.
For many users, this can provide restore points covering the past several weeks.
Users concerned with performance or space usage may also opt to disable System Restore entirely.
Dropbox stores the version history of your files for 30 days.
Or for longer, if you use Dropbox Business or Dropbox Plus with extended version history.
At this point you may have lost data or ended up with a corrupt database and you should seek professional help.