When I try to save something or rename a file/folder it say this error " Read-only file system" or run something as root in the terminal it say this error

sudo: unable to open /var/lib/sudo/"My User Name"/0: Read-only file system 
W: Not using locking for read only lock file /var/lib/dpkg/lock
E: Unable to write to /var/cache/apt/  
E: The package lists or status file could not be parsed or opened.

When I make a Folder the error dialog in the details with Nautilus is this:

Error creating directory: Read-only file system

I would show you I picture of it but it isn't even letting my save onto my flash drive. Please help me.


This worked for me:

First, run this command:

fsck -n -f

Then reboot the machine

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    Do you realize that you answer a question, that is 3 years old. To make it meaningful, it should be useful for many people including beginners. So you must add more details into your answer. Otherwise it might be deleted. – sudodus Jan 6 '17 at 17:55
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    @sudodus You are way out of line to criticize someone for answering an old question on a stackexchange site. The whole point is for these questions and answers to to remain indefinitely as a resource. This isn't some forum site with their typical bias against resurrecting old threads. If you have a reason why a filesystem check would not help the user's situation, explain it. You should not discourage a new user from trying to help. And whoever else downvoted this, explain to us what you downvoted for, don't just mindlessly follow the herd. – msouth Jan 28 '17 at 23:52
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    @msouth, I accept your critical comment. My comment was mainly trying to make the author of the answer improve it - add more details, because I think it is not complete enough to be useful for a beginner. (And I did not downvote it, someone else did). I am sorry that my intention was not clear - the intention was definitely not to discourage anybody, not the author of the answer, and not you. I will try to change my commenting style to make it more positive. – sudodus Jan 29 '17 at 7:48
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    @sudodus my phrasing was too harsh, I'm sorry for that (the site doesn't let you edit comments, but when I realized that, I should have just deleted it and made another comment). My respect to you for taking it so well. – msouth Jan 30 '17 at 0:26
  • Underrated answer. – Etienne Gautier Nov 7 '17 at 15:23

When the system enters a read-only state, it does so to prevent damage to the system. Make sure your HDD is working properly and/or backup your data before doing anything.

I suggest to boot a live USB/DVD, open GParted, and use the check/repair feature.

This is the command to enable writing:

sudo mount -o rw,remount /
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    I can't because I need sudo access and I can't get it. "sudo: unable to open /var/lib/sudo/mathcubes/1: Read-only file system mount: cannot remount block device /dev/sda6 read-write, is write-protected " – MathCubes Apr 28 '13 at 2:44
  • as i said boot up a live disk and use gparted to check/repair the partition, if you don't have a disk you can use partedmagic it is under 500MB in size – GM-Script-Writer-62850 Apr 28 '13 at 3:20
  • How? Do I repair the partition in gparted? – MathCubes Apr 28 '13 at 19:00
  • But What do I do in gpared, reformat it NO! – MathCubes Apr 28 '13 at 20:14

If you are dual booting Windows with Ubuntu and you do not have any error in dmesg, then the problem could very well be caused by Windows.

In Windows go to Control Panel → Power Options and disable Fast Startup. Now boot into Ubuntu.

  • Are you implying that either 1) Windows had the ext4 root file system of OP's Ubuntu installation mounted or 2) the root file system of OP's Ubuntu installation was NTFS? I find that very unlikely. -1 – David Foerster Jul 16 '18 at 17:45
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    I am not implying both. What I mean is that if you can't mount a file system as write on a dual booted system and there are no visible issues with the file system, then the problem could be caused by the Windows Fast Startup You may downvote as you wish, but this is a valid solution for people who dual boot. – Prejith P Jul 17 '18 at 17:52
  • Not for this question though because your solution doesn't apply to it. – David Foerster Jul 17 '18 at 18:04
  • As I had mentioned in my original post, this is the 2nd solution on search for the error "read only file system", which is the same error that you get when trying to mount an external drive in dual boot – Prejith P Jul 18 '18 at 0:45
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    This really worked for me (Ubuntu 19.04). Even though, I wasn't for sure that it'll work but it does. – HV Sharma Oct 28 '19 at 18:12

When accessing an HDD from different OS (Windows & Linux) the disk could contain an unclean file system. So the metadata cached in the OS, deny mounting the disk

To try to correct the mistakes, identify the path of your disk in the Disk app (i.e: /dev/sdb1) and use ntfsfix.

sudo ntfsfix /dev/sdb1


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