Cannot copy to USB - every USB stick is read only (16.04)

My head hurts a little from all this, but hey turned out to be this bug. It's a shame to see the community take such a setback from the dismissal of Unity, and while they start over the giants like Microsoft and OS continue to progress down the road.

killall nautilus

Worked for me.

I found this info. Try this: How to fix read only USB pen drive in Ubuntu. I do not know why every USB stick would be read-only. Hope it helps anyway.

This is how I fixed the permissions of my pen drive that 'suddenly' became readonly.

1. Switch to super user with:
   sudo su -

2. Find in which directory the USB drive has been mounted by running:
   df -Th

   You should get a list of drives and your USB drive should be listed as:
   /dev/sda1 fuseblk 15G 65M 15G 1% /media/someuser/myUsbDrive

3. Change the permissions of your USB pen drive (located at /dev/sda1) with:
   find /dev/sda1 -type f -exec chmod 666 {} \;

   or with

   find /dev/sda1 -type f -exec chmod 644 {} \;

Now your drive should be writable.

---

If the above doesn't work then change the permissions of the directories to make them writable:

find /dev/sda1 -type d -exec chmod 755 {} \;