After a short blackout in the storm night, the external SSD drive on Raspberry Pi did not respond. After reconnecting it, The error dialog was shown with the message: Unknown error when mounting
.
This command solved the problem.
sudo ntfsfix /dev/sda1
After completing the repair, needed to reboot
.
https://askubuntu.com/questions/1236397/ubuntu-20-04-error-mounting-dev-sdb1-at-media