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I have a Sandisk Cruzer 16GB USB flash drive, but it started to show up as 16MB. And I can't use it, it tells me that I need to format the drive or Please insert a disk into drive X. What software do I need to check the flash drive?

I can't format it since the format fails, and it shows as 16MB instead of 16GB.

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was it 16GB before or it has been 16MB from the first day you used it? – user3864 Oct 2 '09 at 21:49
it was 16GB when i bought it – Karim Oct 2 '09 at 21:50
up vote 4 down vote accepted

If all else fails, boot an Ubuntu CD, plug in the USB drive, and format it there. Ubuntu seems quite good at formatting things that Windows considers otherwise untouchable. Once formatted, eject and reboot into Windows and attempt to use it.

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Windows won't do certain things with removable devices, multiple partition support is one of them. If more than one partition is found, or the partition table is corrupted, you can expect behavior like this from Windows. – LawrenceC Mar 11 '11 at 14:30

Many models of the SanDisk Cruzer flash drive come with U3 security software which you need to run to access the drive. The smaller partition contains the U3 software itself, so you can launch it from there.

U3 uses the rest of the space to store your data in an encrypted format.

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Understands U3! – Xavierjazz Oct 3 '09 at 3:36

This sounds like a partition issue, but if you bought it from the likes of Japanese sellers on eBay, be aware that some people are selling tiny (possibly old/refurbished/rebranded) USB drives, which report their size as much more. I poked around one a few months ago, and it even acted like it was still working past its real size, but just got a lot slower, and didn't actually store the data. I've only seen this done with cheap looking drives and unbranded or unusual brand names; not faking a reputable brand/product like Sandisk's. I suspect they've done that too though, or will try it soon enough.

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It seems like you have to allow and create a partition on your disk, if you are using windows, go to computer -> manage -> Disk management the right click your disk -> format and create a new partition, you can also check if it's inactive.


You need to delete the partition then allocate the space again, if this doesn't work, please post more details about your problem

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its not as simple as that, i know that i should partition the drive first. but the idea is that it shows as 16MB instead of 16GB and is not formatable – Karim Oct 2 '09 at 21:46

I just faced a similar problem and found a solution in this Microsoft forum thread:

  1. Open a Command Prompt.

  2. Type diskpart.

  3. When DISKPART> loads, type list disk.

  4. Locate the USB disk number and type select disk #, # being the number of the USB disk.

  5. Type clean, this will remove all volumes on the current in-focus disk by zeroing sectors. As such any files you have on their will also be lost.

  6. Go to Disk Management, and the OS should now report the USB drive with the near total size but as Unallocated.

  7. Right click on the Unallocated for the USB drive and select New Simple Volume.

  8. Follow the wizard to partition the drive. In my case, only File System FAT32 was available.

  9. From this point on, the disk will be at its full size and can be reformated to NTFS if needed

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