Reformatting read only FAT32 USB Stick

Hi,

I have the exact same problem with a brand new ScanDisk. Was playing around with it, partitioning in DU to see what would work with my bluray player without limiting me to 4GB files (nothing btw) when suddenly all options exept 'Verify Disk' were grayed out and disk is 'Read Only'...

The first thing I did is hook it up to a Windows laptop to reformat in there but with no luck: says unable to reformat because the disk is 'read only'. So is there a solution to this or do I have to bin my brand new USB? :/

I couldn't figure out how to do this either, but then I found the eHow page for it!

http://www.ehow.com/how_5103741_reformat-flash-drive-mac.html

This works! it's great 😀 It's really simple - just go into 'utilities' -> 'disk utility' -> 'erase' -> then it should be all good

N.B. Before you 'erase' they external drive, make sure you have a copy of the files elsewhere, otherwise they will be 'erased'

I have exactly the same issue this week with a 3 month old Integral 16GB memory stick. The files on the stick could be read, but it went into read-only mode exactly as you describe. There was data copied on it from a Windows machine, but I had also subsequently been able to copy files onto it using the Mac. Then it went read-only. It is FAT32. Only option in Disk Utility was Verify, which said it needed to be repaired, so selected Repair; the only result was that I couldn't then see any files on the stick, (although the used/available figures on Get info remained the same). I'm not worried about the data on the stick, but I now have a 3 month old 16GB memory stick that is unusable. Alanah's suggestion above to Erase does not work, as Erase is greyed out. The stick also appears as read only on a friend's MAc, and no the stick does not have any switch to set it as read-only.

I also have rather different problems with another memory stick. It also was FAT32 and had data on it from a Windows machine

- first of all it shows as two items in Finder - one a named drive (with data), second a "NO NAME" drive (with no data). They need to be ejected separately. Not an issue as such, but it is worrying.

- secondly I've copied files onto the stcik from the Mac, then deleted some files from it to make more space, but the space is not freed up from the deletions.

The only common issue between these two drives is that I tried (inadvertently) to copy large files onto them and got an error (as FAT cannot handle files about 4GB).

What is going on with memory sticks on a Mac ? I've only had the Mac a month and so far been very pleased with it, but this is worrying as I want to use memory sticks for short term backups of important data, and I now have 2 sticks I can't use. Buying new sticks until they stop working doesn't seem a very sensible solution to me !

If anyone can help with the above, I would be very grateful.

Regarding my problem with the first memory stick as noted in my last post, and following instructions from another discussion, I tried Terminal commands, as follows, with results

ls -ld /Volumes/Untitled

drwxrwxrwx@ 1 colinmoss staff 8192 16 Jan 2029 /Volumes/Untitled

Mount

/dev/disk1s1 on /Volumes/Untitled (msdos, local, nodev, nosuid, read-only, noowners)

So the has no owner, and as far as I can tell the permissions look OK.

The stick does not seem to have failed, since I could (until I tried Repair) read all the files off it.

So I have tried everything I can find now - if anyone can help it would be much appreciated.

Ignore my comments on the second memory stick (post at 11:48 today), I have resolved that by emptying Trash with the USB stick attached. It's the first memory stick mentioned in that post - in readonly mode - that is the outstanding problem. Apple support tell me there's nothing I can do with it on the Mac, that it must have got formatted in a way that the system can't deal with. Any ideas for a utility to format a USB stick with invalid format that an Apple can't deal with ??

I experienced exactly as many of you described but TWICE with two usb drive within just less than 2 months. One is lexar 16GB and another is sony16GB. Apart from having "read-only" status, the Sony usb stops reading sometimes without any reason. Immediately after that, OS X automatically unmounts and mounts the usb drive.
When I used "Disk Drill" to analyze, the Sony usb appears to have "bad blocks". However, I am not sure whether the cause is really "bad blocks" of the usb drive or something related to OS X. I tried in windows to remove read-only status, however, right after things are done and I open the properties of the USB, "Read-only" appears again. Format command seems not to work. So the problem is unsolved for me.
Can any Apple expert solve this problem?

Bump!

Im having the exact same problems, just like the pictures posted. I can't change the permissions (locked to read-only), everything in DU is grayed out except the "Control disc"-option. I've tried "attaching" the USB stick to a Windows PC, doesnt help either. Tried another Mac as well, same story.

And yes, its formatted as MS-DOS FAT32 without any software for the USB stick. It aint even over a month old.

Any suggetions?

Regards.

Make sure your over-write switch on your USB/SD card is not enabled. I had the same problem and remembered that I needed to switch this and voila! Everything is now working both read and write.

vtmaestro

I don't see any definitive answer to this question ... is there one?

I have a brand-new PNY 64 GB USB memory stick that I used to install MacOS Mavericks to my system clean ... now I want to re-use it, I see this .... everything greyed out and no way to change or modify it.

There is no r/w switch that I can see on the device at all ... it's just stuck there ... any procedure to clear this?

I had a emtec 128gb with the same problems.

I sent emteca a email and they sent me a link to a restor tool on there website, it worked but the tool only worked on windows.

Maby PNY has a similar restor tool that will work on your usb??

Oliver, What was your fix for this?

John, any help with what to do when using Windows? have tried various things with no luck.

OH man - Thank you so much, i forgot that a friend of mine, switched to "Locked" i run into the same issue... - thanks! 😀

I was turning crazy but this finally worked for me. The switch was ok but turning it in lock position and back to unlock solde the issue !!!