Ubuntu – My microSD mounted read-only

I finally solved my problem!!!! I used the disk utility tool in ubuntu 11.10 and tried to check file system. It popped up an error saying that the disk was mounted, cation of loss of data. I then proceeded to cancel and unmount the drive, then scan. After about three min a box appeared that said 240 kb of data was giving an error due to a faulty unmount while writing. I hit ok to delete, now my external is up and running with full read/write capability's!!!

This may not answer the problem in the question, but this question is one of the top search results for "ubuntu usb stick mounting read-only". If you're stumbling across this question in your search for answers, hopefully the following helps. This is what solved my own problem.

It's possible your USB stick(s) may in fact be corrupted. Assuming the stick uses the FAT file system, follow this guide.

How to fix read only USB pen drive in Ubuntu

Summary:

1. Identify the mounted USB drive by running df -Th.
   • Example output: Filesystem Type Size Used Avail Use% Mounted on /dev/sda5 ext4 28G 25G 1.3G 96% / udev devtmpfs 2.0G 4.0K 2.0G 1% /dev tmpfs tmpfs 796M 1.1M 795M 1% /run .... /dev/sdd1 vfat 15G 12G 3.6G 77% /media/linux/C38C-099C
2. Unmount the affected drive using sudo umount <mount path>.
   • Example: sudo umount /media/linux/C38C-099C
3. Repair the drive by running sudo dosfsck -a <filesystem path>.
   • Example: sudo dosfsck -a /dev/sdd1.
4. Safely remove the USB stick and reinsert.