USB FAT-32 is read only

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Level 1

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USB FAT-32 is read only

Hello everyone 🙂,

I have a 16GB usb stick and i only use it on my mac. Today i wanted to use it and tried to put some files onto it but it didn't work. The first thing i did is check the info and there it said under Sharing & Permissions: You can only read. Nothing else nothing to change the permissions or anything. Next thing i did was check the internet and see what they are saying... i tried fixing my problem with Disk Utility but it is coming up with an error that says:

Could not change the partition type for /dev/disk0s2 - Resource busy

When i try to erase it, it says:

Disk Erase failed with the error:

Unable to write to the last block of the device.

When i try to verify it there is also an error:

Error: This disk needs to be repaired. Click Repair Disk.

but the all the buttons (Verify Disk Permissons, Repair Disk Permissions, Verify Disk and Repair Disk) are greyed out 😟

The good news is there is only one file on it which i really don't care about, the bad news is i don't want to go to the shops and buy one (only if there is reaaallyyy no way of fixing). I need the USB stick for school so it would be nice if someone could help.

If you want i can post some screenshots of the errors.

Posted on Oct 9, 2013 4:57 AM

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Answer 1

arthur

Level 5

5,242 points

Oct 9, 2013 5:20 AM in response to dmiller2606

There's a small chance that Disk Warrior or Techtool might be able to fix it, or that you might be able to reformat it with a Windows machine.

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Answer 2

Barney-15E

Level 10

112,518 points

Oct 9, 2013 5:28 AM in response to dmiller2606

If a USB stick starts acting flakey, it is probably done.

FAT does not have permissions, so any info in the permisssions section is bogus.

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Answer 3

dmiller2606 Author

Level 1

0 points

Oct 9, 2013 5:28 AM in response to arthur

Sadly my whole family uses Macs so windows is a no go 🙂 haven't tried the software (costs quita a bit, i'm still in school)

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Answer 4

dmiller2606 Author

Level 1

0 points

Oct 9, 2013 5:34 AM in response to dmiller2606

So.. i looked and found out that Disk Drill is a freeware.. i looked onto there and there is a disk image on there with a windows sign.. i remember now that i tried bootcamp. How to reformat it to a normal usb stick since i don't need bootcamp anymore?

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Answer 5

Tony T1

Level 6

10,232 points

Oct 9, 2013 6:38 AM in response to dmiller2606

To reformat, (make sure that you transfed any files you need), then

in Disk Utility, select the USB

Click the Partition Tab

Change the Partition Layout (to one, or more)

Select Format (i.e. If you want FAT)

`

In Options, select GUID if you need a bootable USB:

Then select Apply

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Answer 6

Oct 9, 2013 7:07 AM in response to dmiller2606

You did not provide the manufacturer or model of the usb device. Some have physical read only/write switches. Could it be that your device has this switch and it got moved in your back pack or otherwise by accident?

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Answer 7

Linc Davis

Level 10

209,541 points

Oct 9, 2013 1:05 PM in response to dmiller2606

Some flash drives have a failure mode in which they are irreversibly write-locked by the internal controller when it detects a write error. If the drive doesn't have a write-lock switch (most do not) and you can't erase it in Disk Utility, that's almost certainly what has happened. To be sure, test it with another computer, if possible.

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Answer 8

dmiller2606 Author

Level 1

0 points

Oct 10, 2013 6:03 AM in response to Tony T1

Tried that but it says: Unable to write on last block of the device

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Answer 9

Tony T1

Level 6

10,232 points

Oct 10, 2013 6:27 AM in response to dmiller2606

Did you try Repair Disk? If that doesn't work, toss the USB, it's toast.

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