See this bug.

Run this command to kill Nautilus (Files):

killall nautilus

When you attach your USB key to your laptop:

• run sudo -i (so that you won't type your password all the time)


• run df -Th(to see where your USB stick is mounted)


• unmount your USB stick


• run dosfsck on the device you saw from your previous command. Example: dosfsck /dev/sdc1
  


• remove and reattach your USB stick

Problem should be solved now.

Now, for your HDD, please follow the answer to this question. It is about an external HDD but it is the same thing for your case.

I got the same error when using GParted to set partition table and format my USB stick.. after that all USB drives went to "read-only".

But under root copying worked fine...

Issue was gone after machine restart. So I guess that this problem may occur when using GParted.

I had this problem too. I got an error while copying to my usb stick, I am using Mint 17.1 cinnamon, kernel 3.13.0-43 with caja file manager.

When I looked at the media directory in terminal 'dir /media' I saw that the layout has changed, normally you expect to see the drives listed here, but now they are listed under your username, and guess what? That username has only ROOT permissions.

What I did was to type

sudo chown [username] /media/[username]

and

sudo chgrp [username] /media/[username]

where you replace [username] with your user name, removed the usb stick, waited and then put it back in, problem solved, I can now write to it!

I've been having the same problem on Ubuntu, and none of the answers given here so far worked for me. Here's what I tried:

• Format the device using GParted. I even tried re-creating the
  partition table, without success.


• Check the device with fsck. No issues were found.


• Fixed the permissions of the mount point. Turns out that the mount point was root owned, but even after making myself the owner, I could only write to the device from the command-line (I still could not create files from the GUI).

When I connect a USB stick, it gets mounted under /media/<username>/<label>/, where <username> is my username and <label> is the label of the USB stick or storage device.

I looked again at the permissions:

$ ls -ld /media/<username>

drwxrwx---+ 2 <username> <username> 4096 Mar  4 18:32 /media/<username>

Notice the + at the end of the permissions. That's new to me and I never noticed it before. It means the directory has extended permissions called Access Control List (ACL) (see this related question). I listed the ACL details for this directory:

$ getfacl /media/<username>

# file: <username>/

# owner: <username>

# group: <username>

user::rwx

user:<username>:r-x

group::---

mask::r-x

other::---

As you can see, there is an additional entry user:<username>:r-x for my username, which only gives me read access. I fixed this with a simple command:

setfacl -m u:<username>:rwx /media/<username>

I detached my USB devide, attached it again, and the problem was solved.

I formatted using Gparted. That wiped all data in the disk and it turns out it also fixed the problem.

When you ran mount only sda5 (your /) was mounted, and it was read-write (rw) so you should be able to write to it. Normally, most of the directories like /sys, /bin are only writeable by root (you'd need sudo first), but your home folder should be writeable to your regular user.

Can you create any files in your home folder? Maybe your gui file manager is stuck thinking they're read-only, if you try in a terminal does it work? For example, do these commands work?:

cd ~

touch newfile001

echo stuff >> newfile001

cat newfile001

If those work successfully then you can write to your HD (sda5).

For the USB drive, after it's plugged in and mounted, look at mount to find it (the /dev/sdb1 ... line) and see if the mount option in the ()'s is rw (read-write) then you should be able to write to it. If it's ro (read-only) try this and see if it changes:

sudo mount -o remount,rw /dev/sdb1 /media/simon/LYDIA

If the filesystem (fs) has errors it may get mounted as ro, there should be messages about it in dmesg & /var/log/syslog too. This is what your logs show:

[  159.366772] FAT-fs (sdb1): Volume was not properly unmounted. Some data may  

be corrupt. Please run fsck.

[  159.383252] FAT-fs (sdb1): error, fat_get_cluster: invalid cluster chain (i_pos 0)

[  159.383258] FAT-fs (sdb1): Filesystem has been set read-only

That includes a clue to how the fs could have gotten corrupted - "not properly unmounted", you should always unmount before unplugging anything. Most file managers have an "eject" to help with that.

The dmesg log also say how to fix it: fsck can try to fix fs errors, it attempts to pick the right check program, or you can pick one explicitly with fsck.vfat or fsck.[other] pressing TAB after fsck. should list options.

• For a FAT system (often have to run it twice, doesn't always fix all errors the first time)
  
  
  
  • 
    fsck.vfat -vaV [device] should work automatically (-a) & display more info (-v) & do a "verification" pass (-V), or just:
  
  
  • fsck.vfat -a [device]
  
  
  
  

NOTE: This will not guarantee that the filesystem will stay fixed, it could get corrupted again & it may be impossible to know exactly why. Always unmount / "eject" before removing USB drives.

Note if a fs mounts as rw, but then errors are seen & it gets automatically remounted as ro, the mount command may still report it's mounted rw. Looking at this file with less /proc/mounts should usually show more reliable information (see man mount).

If something is mounted rw but you still can't add/delete/edit files on it, you may not be the owner of the files. In some fs's you can chown to become the owner, but a FAT32 fs like on sdb1 doesn't have those permissions; they're set when it mounts with the mount option uid=value (value is your userid, learn it with echo $UID or id -u) then you can try this & see if it works afterwards:

sudo mount -o remount,rw,uid=[userid] /dev/sdb1 /media/simon/LYDIA

• Note: Sometimes, you may need to restart your gui file manager to get it to "notice" the mount change that lets you write to the filesystem/drive, but a terminal should always work.

Or if the above doesn't work, try sudo su to "become" root, to see if anything can write to files on the USB (with touch, echo, etc)?

Goto Disks.

Select your USB drive.

Click on Additional partition options and select Format Partition.

Then select erase Overwrite existing data with zeroes(slow) and type FAT.

I have tried many things after searching on internet but this worked for me.

Quick fix methods:

Method 1

Sometimes we can accomplish the task from bash without trouble
I usually do (no sudo required)

mkdir /media/$USER/mydrive/myfolder

cp -r src/ /media/$USER/mydrive/myfolder

However, sometimes, when I need to use file browser,

sudo nautilus /media/$USER/mydrive/

Note: this is a quick fix, use it only if you get frustrated because no other answers above worked

Method 2

Reboot OS

As like in wayofthefuture's answer above when you're using Nemo (like me, if you use the Cinnamon desktop environment) try:

killall nemo

try below strategies

1. 
   

   edit /etc/fuse.conf as superuser

   
   
   

   change #user_allow_other to user_allow_other

   
   


2. 
   

   enable write support for external devices

   
   
   
   
   
   • 
     sudo apt-get install ntfs-config
   
   
   • sudo ntfs-config
   
   
   
   

This is because your file system is NTFS and it is in an unsafe stat, maybe you are using your disk in windows, one of the reasons is that you hibernated the windows or fast restarted it., so use one of these steps:

1. 
   

   unmount the media using the below command, go to windows (maybe Dual boot mode or maybe in an another computer) and shut down the windows completely, not hibernate or fast restart,

   
   
   

   sudo umount /media/"your media label"

   
   

then come to Linux again and mount your media using this command:

'sudo mount -o rw,mount /your media'

2. 
   

   if you are using macOs , plug your media to your mac device and use this command:

   
   
   

   'sudo /usr/sbin/diskutil disableJournal /Volumes/name-of-media'