Disk full error

1. Check if you got enough disk space left.
2. Check your download path.
   Depending on your OS (especially Linux/BSD [also QNAP/Synology]), file-systems are case-sensitive so in your currently used path there might indeed not be enough space left and/or you've mistakenly chosen the wrong path.
3. Especially when using Docker as a beginner, application paths can be tricky.
   Re-check the tutorial you've used to setup JD via docker and check your paths!
4. If you are using JDownloader on Synology hardware, check this article (scroll down):
   You are most likely using a download path that leads to your system partition!
5. For advanced users: You can disable the free space check as follows:
   Go to Settings -> Advanced Settings -> Search for GeneralSettings.freespacecheckenabled -> Disable this