Unable to save files in Firefox, /tmp has become read-only after upgrade

Question

I recently upgraded to 18.04, and found out that when I tried to save files in Firefox I got an error saying that the "could not be saved, because the disc, folder, or file is write-protected. Write-enable the disc and try again, or try saving in a different location"

After doing some digging I discovered that /tmp had become read-only since the upgrade. Is there anything I can do?

I tried the answers outlined here, but none of them worked.

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Output of ls -ld /tmp :

drwxrwxrwt 21 root root 69632 Apr 28 12:10 /tmp

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Output of mount | grep tmp:

udev on /dev type devtmpfs (rw,nosuid,relatime,size=3993816k,nr_inodes=998454,mode=755) tmpfs on /run type tmpfs (rw,nosuid,noexec,relatime,size=804648k,mode=755) tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev) tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k) tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755) tmpfs on /run/user/128 type tmpfs (rw,nosuid,nodev,relatime,size=804644k,mode=700,uid=128,gid=142) tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,size=804644k,mode=700,uid=1000,gid=1000)

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Output of df /tmp:

Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda5 25087084 17130836 6658840 73% /

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Output of mount | grep /dev/sda5:

/dev/sda5 on / type ext4 (ro,relatime,errors=remount-ro,data=ordered)

Answer 1

It looks like your "/" has been remounted to "ro" most likely due to "errors=remount-ro". Check your /var/log/syslog and "smartctl -a ".

We had this happened to us once when the hard drive was on the brink of total failure. You want to act quickly because it deteriorates very fast.