if you are experiencing problems with Linux or Linux Virtual Machines as:
"read-only file system"
on file operations or
"/etc/mtab is not writable"
on return of typing command “mount”.
Errors are like this:
mount: warning: /etc/mtab is not writable (e.g. read-only filesystem). It's possible that information reported by mount(8) is not up to date. For actual information about system mount points check the /proc/mounts file.
Run fsck to fix the device disk, then reboot afterwards