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
The command line procedure is not simple, but it is the most likely thing to work (and it doesn't require installing any new software).
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 <ENTER>
and you'll get a listing of all drives on your machine.
Type
select disk # <ENTER>
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 <ENTER>
to get a listing of all partitions on the disk.
If you're sure you have the right disk/partition, you can then repeat typing
select partition # <ENTER>
delete partition <ENTER>
until all partitions are removed from that drive (you may need to type delete partition override for protected partitions).
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. Instead, enter diskpart again, and select the disk. Then type
create partition primary <ENTER>
Once you have created the partition, exit diskpart and, in the command promt, type
diskmgmt.msc <ENTER>
This will provide a reliable way to create a FAT partition.
On the drive you would like to format:
format.allocation unit size, select defaultFile System, select exFAT (or FAT32 for smaller disks)The format may take a while, depending on the disk size, be patient.
This should fix partition troubles on any readable USB flash drive.
You should try BootIce. BootIce is a portable, free utility designed to directly customize and fix drives at a deep level. It is able to edit, restore, install and backup MBR, PBR, partitions and sectors of drives.
CAUTION: Because of its powerful capabilities, using this program can render your drive non-functional. There is no Reverse option to recover from changes made through use of this utility. Always use caution when using BootIce and make sure you know what you're going to do is the way to what you want to accomplish before attempting to make use of its functions.
As I happen to have a flashdrive with this same problem, I'll add a walkthrough below with the precise steps on how to fix it. But first, a bird's eye view of the problem in My Computer:
Compare that to the results in DiskPart:
The drive's original size is 32GB, however incorrectly shows as only 242MB. To correct this, proceed as follows:
How to recover a flashdrive's full capacity using BootIce
http://www.softpedia.com/get/System/Boot-Manager-Disk/Bootice.shtml
Extract the .rar file into a location of your choice. As BootIce is a portable program, you can run it from flashdrive or external HD.
Verify the drive you have is the one with the problem. ATTN: Deleting partitions will erase all data. Make sure you back up any important files or data you do not want to lose before proceeding.
Insert the verified USB with the issue into your computer's USB port.
You will need Administrator access to run BootIce as it requires formatting priviledges. Right click BootIce and select Run as Administrator.
Congratulations, your drive is now ready for use!
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!
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.
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 you want to edit.
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 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.
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.
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
I've added my own answer to this because the current best answer is a long-winded graphical solution, and the only other command-line solutions are longer than they need to be or leave whole stages of the process to be completed in the GUI. This is currently the only pure command-line solution, and I like to think it's also a pretty simple one.
Start by opening CMD as an Administrator (open the Start menu, type CMD, right-click and select "Run as Administrator").
Type:
diskpart
...to start Windows' command-line disk partitioning utility.
Next, type:
list disk
...to list all available hard-drives. Compare the sizes of the listed drives, and when you're certain you have the right one, type:
select disk #
...where # is the number of the drive that you want to select.
This is the first major difference to the other command-line solutions given to this question - listing, selecting and then deleting individual partitions is cumbersome, and when the purpose is to remove all partitions, it makes much more sense to use clean, which does the exact same job and does it quicker.
To remove all partitions from the selected disk, type:
clean
...and wait for the process to finish.
Finally, type:
create partition primary
...to create a single partition covering the entire disk - this is the "default" configuration, suitable for most purposes. You can repeat this step to create as many partitions as you'd like. Remember that an MBR disk can contain a maximum of four primary partitions*.
Once a primary partition has been created, the drive should be back to its original size.
Having restored the drive to its original size, you'll still need to format it with a file system to make it usable. This is where the other answers either stop short or delve into the GUI, but this part of the process can just as easily be done from within the command-line, and it makes little sense to go most of the way via the CLI and then use the GUI only to format the drive... especially when the command-line feels way cooler.
To format the disk, type:
format quick fs=fat32
...replacing fat32 with the file system you want to format the disk with. Use fat32 for a disk that will be compatible with the most amount of systems (including media players, Kodi boxes, Android boxes, etc.), or ntfs if you need to support individual file sizes larger than 4GB.
Finally, type:
assign
...to assign your newly-formatted disk a drive letter, making it visible to Windows.
Your necessary disclaimer that diskpart is a disk-claimer. The command line is dangerous, we all know this, etc., etc. However, nowhere is this more true than within diskpart, where a drive's number can change at any given time for a multitude of reasons, which means it can take entering a single mistaken digit for you to kiss goodbye to all the data you have on your drive. I cannot emphasise this point enough, having just spent the better part of a week trying to recover a disk I'd accidentally set diskpart on after running it for what must have been the umpteenth time in a night. The command-line is a beautiful, powerful tool, but with that power comes danger. Use it with caution, and coffee in your bloodstream.
If something is wrong with the partitions then you need to change them.
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.
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.
Did you try the HP USB FORMAT UTILITY, if this can't format it right, then it's bad, download here:
