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My USB drive used to be originally 8GB when I bought it.

I'm trying to reformatted in Windows 7 by right clicking on the drive and selecting Format.... But the capacity only shows 250MB.

Is there something I can do to get the original size back? Maybe it got partitioned in a weird way?

The flash drive is a SanDisk Cruzer Micro 8GB. I got it from Wal-Mart but this is the same drive. http://www.amazon.com/SanDisk-Cruzer-Micro-Flash-SDCZ6-8192-A11/dp/B000UZN2ZK

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Where did you buy the flash drive from? –  music2myear Jan 25 '12 at 21:33
    
Added more about the flash drive. –  this is a dead end Jan 25 '12 at 22:18
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Ok, then we can be reasonably sure this isn't a fake flash. Good. Then you're just looking at corruption, drive damage, or partitioning issues. –  music2myear Jan 25 '12 at 22:20

9 Answers 9

up vote 24 down vote accepted

You should try BootIce (the link to author's webpage is down, so you will have to google for it).

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Thank you. This worked and was easy to use. –  this is a dead end Jan 26 '12 at 0:00
    
I'm glad that this helped. –  thane Jan 26 '12 at 7:02
    
+1 I've never stumbled across that tool before, very helpful, thank you! –  Basic Nov 8 '12 at 2:09
    
An Anonymous User suggests: It Is Better To Use .. HP Usb Disk storage Format Tool And .. Use It.... .. Step : 1 Download HP Usb Disk Storage Format Tool On Google. 2. Run As A Administrator In Case Windows 7 and 8 3. Go To The Device : Select Pen Drive Letter .. Which You Wants To Format. 4. File System : NTFS OR FAT32 5. If You Want Quick Format .. So Push or Click On Start Button... If You Wants Full Low Level Format . Then ... Un Check Quick Format Level..... 6. Wait For Process 7. Your Lost Storage Capacity Gain 8. Enjoy !!! –  Psycogeek Sep 1 '13 at 20:02
    
In case you still want to use the BOOICE app (it worked great for me) here pendriveapps.com/bootice-partition-flash-drive-edit-boot-sector is a link with current info about it along with author's website and download link for the app itself. –  Neven Boyanov May 21 at 8:20

the command line procedure is not simple, but it IS the most likely thing to work.

When re-formatting the "drive" you're actually only formatting a partition on the drive. You need to use the diskpart utility to remove the partitions and create 1 single partition covering the full volume.

diskpart can be a bit dangerous, because if you pick the wrong disk or partition, you can remove data or partitions that are extremely, EXTREMELY important and lose all data on your machine. Proceed with extreme caution!

Open up a command prompt as administrator (open the start menu, type cmd and press enter.)

Type diskpart and press Enter. You'll end up with a new prompt that looks like this: DISKPART>

Type list disk, and you'll get a listing of all drives on your machine.

Type select disk # to select a disk, where # is the number of the disk Windows screw-balled. usually, the device is disk 1, but it's always best to make sure.

Then type list partition to get a listing of all partitions on the disk.

If you're sure you have the right disk/partition, you can then type select partition # and delete partition until all partitions are removed from that drive.

Once the drive is empty, exit diskpart and remove the drive. wait at least 5 minutes, then re-insert the drive. DO NOT CLICK FORMAT- this will most likely re-create the problem. enter diskpart again, and select the disk. then type create partition primary.

once you have created the partition, exit diskpart and, in the command promt, type diskmgmt.msc. this will provide a reliable way to create a FAT32 partition. on the drive you would like to format (NEVER TOUCH DISK 0), right click and select format. the 'allocation unit size' option should be default, and the 'File System' option should be set to FAT32. the format may take a while, depending on the disk size, be patient.

this should fix partition troubles on any readable USB flash drive.

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Thanks. This fixed my problem. –  Michael Steele Feb 27 '13 at 22:39
    
This is a really good answer. I've always prefer to do all by my self not with third-party tools that i do not have control of. Thanks. –  mnmnc Nov 5 '13 at 15:27
    
Why we should wait for 5 minutes? –  ABFORCE Jun 17 at 9:11

When re-formatting the "drive" you're actually only formatting a partition on the drive. You need to use the diskpart utility to remove the partitions and create 1 single partition covering the full volume.

diskpart can be a bit dangerous, because if you pick the wrong disk or partition, you can remove partitions/disks/etc. that you didn't want to remove, and lose all data on your machine. Proceed with extreme caution!

  1. Open up a command prompt as administrator (open the Start menu, search for "Command Prompt", right-click and select "Run As Administrator". You'll get a black text-only window that pops up.

  2. Type diskpart and press Enter. You'll end up with a new prompt that looks like this:

    DISKPART>
    
  3. Type list disk, and you'll get a listing of all drives on your machine.

  4. Type select disk # to select a disk, where # is the number of the disk you want to edit.

  5. Then type list partition to get a listing of all partitions on the disk.

  6. If you're sure you have the right disk/partition, you can then type select partition # and delete partition until all partitions are removed from that drive.

  7. Once they're all removed, type create partition primary to create a new partition that covers the entire drive. Alternatively, at this point you can create multiple primary partitions of varying sizes as needed by appending SIZE=# (in MB) to the end of the create partition statement. Not specifying a size will use the entire disk.

  8. Once the partition is created, type exit twice (to exit diskpart, and then to close the command prompt) and then use the format option to format that blank partition.

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You can just do this from the Disk Management console if you'd rather not fight with a command line. It's safer for the uninitiated. –  Shinrai Jan 25 '12 at 15:22
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I'm a command-line junky... I admit. That... and sometimes the windows disk-management utility won't allow you to do some things. –  TheCompWiz Jan 25 '12 at 15:24
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@Shinrai Sadly, the Disk Management Console doesn't let you mess with partitions on thumb-drives. It is hard-coded to only allow 1 partition on removable storage. –  TheCompWiz Jul 10 '13 at 13:10
    
... but then again... Windows doesn't understand multiple partitions on a single removable drive either... –  TheCompWiz Jul 10 '13 at 13:11

If something is wrong with the partitions then you need to change them.

  • Open your startmenu and search for diskmgmt.msc to open the partition manager,
  • Select the usb device
  • Delete all the partitions you don't want (preferably the ones from your usb drive),
  • Create one big partition (if you want to use it on other operating systems choose exFat or FAT32),
  • Format the new partition.
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Under some circumstances (I'm not sure what they are) the option to delete the primary partition is missing. I had to use BootIce as per @thane's answer to wipe all partitions –  Basic Nov 8 '12 at 2:10
    
These instructions may work for normal hard drives, but I do not think they work for drives that Windows detects as removable. –  Michael Steele Feb 27 '13 at 22:34

There appears to be a problem these days with fake flash drives ( google: flash drive scam ). In many cases, the drive has been altered to report a higher amount of storage than is really there, and if you attempt to use it, you will wind up with lost data.

See for instance: ( http://sushifury.com/2010/03/i-got-sold-a-fake-usb-flash-drive-on-ebay-heres-how-i-fixed-my-situation-and-how-you-can-avoid-this-situation-yourself/ )

If you got it for a really good price, consider examining your flash drive more carefully.

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I purchased it from Wal-Mart and I was able to burn a 4GB operating system on it once that worked. I doubt it's fake but thanks for the warning. –  this is a dead end Jan 25 '12 at 22:24
    
In case that link goes down, the testing program is H2testw, and it's worth running on new drives even if you think it's good - if nothing else, it'll tell you the speed of the drive and verify there's nothing wrong with it. –  Bob Nov 17 '12 at 7:48

Use this empty bootsector program if you want to reformat your device when you have written multiple partitions on you flash drive and Windows doesn’t recognize the full device size anymore. Just restore it in device mode

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Windows Disk Management Console often doesn't work for USB drives to remove the partition. You will most likely need to use the command line.

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My usb drive only showed as about 20 mb in size after using it to make a bootable linux drive.

I successfully used a tool called SD Formatter 4.0 to format it with the actual size. Have a look here Restore Your USB Key to it's original state

After having tooled around with a USB Linux version using your image overwritten or multi partitioned flash pen drive, you might find it necessary to revert it back to a single fat partition (restore the flash pen drive to it's original state) that can again be read by all computers. Windows users can follow the Windows instructions below to Restore a Flash Drive using the HP USB Format Tool. For those working from Linux this task can easily be accomplished via the Linux Flash Drive Restoration tutorial that follows.

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protected by Community Dec 4 '12 at 20:31

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