USB Flash Drive Readonly but has spotlight folder

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Level 1

8 points

USB Flash Drive Readonly but has spotlight folder

I got some photos from a friend in a USB flash drive, formatted as FAT-32. I copied some files and left it connected to my Macbook Pro (via a USB Hub, if that is important) for about a week. After that the disk is 'read only', on my mac AS WELL AS on my friend's PC. I first thought that it was always read only, but it has a ".Spotlight-V100" folder - which means it was writable before. (The message I get on Mac is "read only file system" and on a PC I get "The hardware is write protected").
(It is possible that the system crashed when the drive was connected, but I am not sure)
Is this something to do with spotlight? Is there a way that I can make the drive writable again? Can someone help me?

Macbook Pro, Mac OS X (10.5.3)

Posted on Jul 5, 2008 5:14 PM

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Answer 1

Nivas R Author

Level 1

8 points

Jul 5, 2008 6:17 PM in response to Kappy

In "Sharing and Permissions" I see "You can only read" (just this text. Nothing else).
Also, this drive is never listed in the sidebar, but there is an icon on the Desktop. (and I am sure I had it in the sidebar before, during that one week I had it connected.)

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Answer 2

Kappy

Level 10

362,007 points

Jul 5, 2008 6:31 PM in response to Nivas R

Select the drive icon, press COMMAND-I again. In the Ownership and Permissions click on the little lock icon and authenticate when requested. Change permissions for "you" to read/write. Also be sure the option to "Ignore permissions on this volume ..." is unchecked.

You should then open the Terminal application and enter at the prompt:

chmod 775 [note the space after 775] Drag the disk icon into the Terminal line after the space.

Press RETURN.

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Answer 3

Nivas R Author

Level 1

8 points

Jul 6, 2008 6:34 AM in response to Kappy

In "Sharing and Permissions" there is nothing except the "You can only read" text. No icon, nothing. Anyway I tried chmod 775 but I get the message: "Read only file system".
I checked disk utility again - the file system is FAT 32 and in Information in Disk Utility, "Writable" is "No".
Is it possible that it has something to do with the hardware? Can a prolonged connection of a USB flash drive to a mac cause some harm to the drive?

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Answer 4

V.K.

Level 9

56,192 points

Jul 6, 2008 7:31 AM in response to Nivas R

Kappy's commands would not work on a FAT32 drive. FAT32 file system doesn't understand unix permissions and one can not change them from OS X. the permissions are treated as 777 as read/write by everyone.

What you see is likely due to a file system issue or a hardware problem as you suspect. If the system detects an issue with a file system it can go into a protective mode and treat the file system as read only no matter what this file system is. You might be able to fix it by repairing the drive. This would have to be done from windows using [chkdsk|http://support.microsoft.com/kb/315265]. If that doesn't work, try reformatting the drive. If that fails, the drive is toast and you should get a new one.

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Answer 5

Nivas R Author

Level 1

8 points

Jul 10, 2008 9:56 PM in response to V.K.

I tried to chkdsk/format but both returned "The drive is write protected". I think I have to get a new one. The good news is that I did not lose any data (Disk is read only but the data is still there) Anyway, thanks V.K and Kappy, for the help.
(I still wonder whether just connecting to a USB Hub can damage a drive. My USB hub has a power supply. I don't know whether that could be a reason. Still, thanks!)

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