How can I troubleshoot a read-only file system error on Linux x86_64?

Troubleshooting involves several steps. First, check disk space using `df -h`. Second, run `fsck` (file system check) on the affected partition (e.g., `fsck /dev/sda1`). Third, examine system logs (`/var/log/syslog` or similar) for clues about the cause. Fourth, if the error persists, consider hardware issues with the hard drive or SSD.