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I have a "SanDisk Cruzer USB Device" which is labelled for 8GB and always was 8GB. I didn't use it for a while and now it lists 3.49GB on my PC. I think I've done something to it a while ago, but can't remember what I was doing.

I've tried different PCs on that, with different OSs (Ubuntu Server 12, Ubuntu Desktop 10, Windows 7, Windows XP). They all listed the device for around 4GB. I also tried formatting but in the format dialog (of windows XP) I could only choose 3.50GB capacity (whether I'd select FAT32 or exFAT).

What might the problem be? How can I resolve this issue?


I runt fdisk -l /dev/sdb on Ubuntu and found:

Disk /dev/sdb: 3763 MB, 3763600896 bytes
116 heads, 62 sectors/track, 1022 cylinders, total 7350783 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x69686373

This doesn't look like a partition table
Probably you selected the wrong device.

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   ?  4281232757  1652651905   833193222+  6d  Unknown
/dev/sdb2   ?  1141509631  1685422960   271956665   66  Unknown
/dev/sdb3   ?  1937007983  1937010555        1286+  65  Novell Netware 386
/dev/sdb4      2885681152  2885736393       27621    0  Empty

Partition table entries are not in disk order
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What is the output of sudo fdisk -l /dev/sdX on Ubuntu? (Replace sdX with the partition assigned to your USB flash drive.) –  jaume Feb 28 '13 at 12:44
    
@jaume I added it to my question –  Camil Staps Feb 28 '13 at 12:52
    
I forget if removable disks are shown in the disk management software built into Windows. It looks from this you have several Unknown paritions on the device. Its entirely possible the device is just broken or is beyond its lifespan in writes ( flash drivers are design this way ). –  Ramhound Feb 28 '13 at 12:59
    
@Ramhound that's a pity.. is there anyway to repartition the device to get the 8GB back? -- also, why the downvote? –  Camil Staps Feb 28 '13 at 13:01
    
Ubuntu reports 4 GB now... I think the USB drive is going haywire, I'd recommend that you stop using it. I don't see how you can get your 8 GB back. –  jaume Feb 28 '13 at 13:02

3 Answers 3

up vote 2 down vote accepted

I think the USB drive is going haywire, I'd recommend that you stop using it.

Ubuntu reports 4 instead of 8 GB:

$ sudo fdisk -l /dev/sdb
Disk /dev/sdb: 3763 MB, 3763600896 bytes
116 heads, 62 sectors/track, 1022 cylinders, total 7350783 sectors
(...)

And if you look at fdisk's output more closely you will notice that the start and end sectors make no sense at all and don't match the total number of sectors on the Cruzer:

Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   ?  4281232757  1652651905   833193222+  6d  Unknown
/dev/sdb2   ?  1141509631  1685422960   271956665   66  Unknown
/dev/sdb3   ?  1937007983  1937010555        1286+  65  Novell Netware 386
/dev/sdb4      2885681152  2885736393       27621    0  Empty

Something's wrong with the USB flash drive. I don't see how you can get your 8 GB back.

share|improve this answer

try to use " HP USB Disk Storage Format Tool " that can be downloaded from cnet but if after quick format you have same issue try full format with that tool.

share|improve this answer
    
This tool is pretty much the same as Windows XP's tool and it didn't work. Thanks for the idea though and it might help others :-) –  Camil Staps Feb 28 '13 at 13:34
    
@Kaveh - Why wouldn't he just use the built-in disk manager within Windows. –  Ramhound Feb 28 '13 at 14:03
    
@Ramhound I'm not sure, some flash does not partitioning but if this model support that it's a good idea –  Kaveh Feb 28 '13 at 14:05
    
This lower-level format/init tool helped restore the full factory 8GB capacity to a USB stick, when the above naive high-level partition reformat kept it at only 4GB. –  Marcos Aug 13 at 21:11

Put the device in your windows machine and do the following:

  1. On the start menu go to Run
  2. In the box enter 'compmgmt.msc'
  3. In the managment console select from the tree on the left 'Disk Managment'
  4. On the right in the top list of disks, identify your flash drive and click the drive letter
  5. That drive should now be focused in the list below.
  6. I am assuming you are going to see a primary partition and a bunch of logical partitions
  7. Delete the partitions until there is only one.
  8. Format the only partition left.

This works in 85% of the problems with these drives I have seen. Occasionally someone will format one to be a boot device or a live linux distribution and there are a pile of inactive partitions for swap space and such.

As was mentioned in the comments, there is also a finite amount of writes for flash devices, but unless this was used as a primary os drive for a few years, I highly doubt you reached the write life on it.

I rarely suggest third party tools, however I have used this partition wizard a few times to fix stubborn partition issues. It is fairly intuitive and easy to use.

Finally a warning: If you are not sure which drive you need to fix the partitions on, or you are at all confused about the drive letter, stop before you start. You can seriously wreck a machine if you mess with the partitions on the wrong disk.

share|improve this answer
    
I made all partitions one on linux, but the total size is 3,50GB, unfortunately. –  Camil Staps Feb 28 '13 at 13:37
    
when you view it in windows does it show any un-allocated space? –  Pow-Ian Feb 28 '13 at 13:43
    
No <!-- random text to get the minimum //--> –  Camil Staps Feb 28 '13 at 13:48
    
I guess it is just a bad drive. –  Pow-Ian Feb 28 '13 at 13:54
    
Okay, thanks anyway :-) –  Camil Staps Feb 28 '13 at 13:54

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