Windows 7 will not automount (assign a letter) a flash drive, behaves really strange

Question

I have a SanDisk Cruzer Micro 4gb that I use often. Today, after using it to install ubuntu on another pc and plugging it to my main computer, windows 7 refuses to mount it (IE the drive does not appear in "my computer").

The volume DOES appear in the disk manager and device manager ("Disk 4"):

but when I try to assign a drive letter (via right click > change drive letters and path) I get "The system cannot find the file specified"

The really weird thing is that if I disable and re-enable the driver in the device manager, suddenly everything works and the flash drive gets assigned a letter and shows up in "my computer" (The letter J: in this case). I can even change the drive letter now without the error, but this does not remedy the problem.

Even so the next time I unplug and replug the device it reverts to it usual annoying self and does not get mounted (doesn't get a drive letter or appear on "my computer")

Things I've tried to no avail:

• Rebooting
• Plugging and unplugging on different USB ports
• uninstalling and reinstalling the driver (as mentioned has no permanent effect)
• Changing the drive letter
• Trying the drive on a different computer (flash drive gets mounted and works perfectly)
• Re-formatting the drive to FAT32\FAT (look at comment below)
• Trying in safe mode (still doesn't work)
• Trying to assign a letter with Diskpart (fails with "the system cannot find the file specified") link: i.stack.imgur.com/QR3aI.png
• Trying to enable\disable "automount" with diskpart
• Praying to the flying spaghetti monster (still not go :( )

I'm at a loss... reinstalling windows over this issue seems like overkill. Please advise!

Answer 1

I ran into the same problem and experienced the same set of symptoms as you.

I eventually resolved this problem by using a third party partition tool to do the following:

1. Wipe all partitions on the flash drive.
2. Create a new FAT32 partition encompassing the whole flash drive.
3. Manually set the drive letter.

In my case, I used the free download MiniTool Partition Wizard Home Edition.

Worked like a charm. No reboot required.

Best of luck!

Answer 2

(Warning this command will overwrite the data contained on the drive specified. With the following command be thoughtful to get the drive letter/path correct.)

I used Cygwin and dd to blank the partition table, after that Windows was able to format it. Use cat /proc/partitions to see the drive and the partition table can be blanked with the command:

dd if=/dev/random of=/dev/sd[Cygwin path letter]

The command will only need to run for a few seconds as the partition table is a the beginning of the drive.

Answer 3

Have you tried reformatting the usb drive. I noticed that in the disk management utility it labeled your drive as a (Logical Drive) as opposed to a active, primary partition. I just tried it with a spare usb drive and after a standard format for me I got:

I also heard somewhere that some logical drives have conflicts when assigning letters. It might have only been with networked drives though.

Answer 4

The Windows disk manager can corrupt the partition table, try using Gparted to create a new partition table and a primary fat32 partition with no flags.

Answer 5

I've read out your problem and here is your solution:

1. Open run dialog box
2. Now enter diskpart.exe hit enter
3. Now disk part opens
4. Enter list disk and hit enter
5. Remove all your storage flash except your pendrive
6. Now enter select disk 1 hit enter
7. Now type clean hit enter
8. Wait till it completes
9. Now type create partition primary
10. Wait till it completes
11. Now type select partion 1
12. Now type format fs=fat32
13. You can use fat and ntfs file system as well
14. Now type active
15. Now type assign
16. You've done