Rewritten 11/21/09
Intro
There are many possible and varied reasons why Windows might
=> Stop recognizing your USB drive
=> Stop displaying that familiar USB drive letter in Explorer or My Computer
=> Report the drive media is write protected
=> Report it can't read the USB drive (e.g. it says the drive is unformatted or a raw filesystem or reports the incorrect partition size)
You'll find a number of troubleshooting steps below as well as links to related USB topics
If you’re not familiar with USB troubleshooting, suggest you
> Start by going through the General Steps sequentially
> Followed by Additional Steps and related links as might apply
Otherwise, feel free to start and use the information below however you see fit!
Also: To avoid problems with USB devices in the future also see How to Avoid Problems with USB Storage Devices
Related Links
USB Device Problems? Check for Windows Updates
How to Check Hardware / Connection Issues with your USB Device
CD/DVD or Disk Problems? How to Fix Problems Caused by Filters
How to Reinstall Your USB Controllers and Motherboard Chipset Drivers
How to use G-Parted-Live-CD for USB storage device problems
How to Avoid Problems with USB Storage Devices
Troubleshooting
1. General Troubleshooting Steps for: All USB storage device problems
Run Windows Update
=> Windows has a long history of USB problems and bug fixes
See USB Device Problems? Check for Windows Updates
Uninstall then re-install your USB storage devices (such as USB CD/DVD, flash and hard drives)
=> Your system may still have old USB installation data which conflicts with the USB devices you're now trying to use
Use the Drivecleanup tool to uninstall and remove old installation data for unplugged USB storage devices
See How to use the DriveCleanupTool
Unplug other USB devices
=> A different USB device might be the real root cause of your problem
Unplug your other USB devices to take them out of the equation when you’re testing and trying to fix your USB drive
It’s OK to leave USB mice and keyboards plugged in. However
>> Note some tests in this Guide that specifically require otherwise
>> If you have the option to use a non-USB mouse and keyboard while testing, IMHO "you may as well use ‘em"
Undock any docking stations. Disconnect hubs
Plug your USB drive directly to your computer (Don’t use external USB hubs while testing except when told otherwise!!)
Connect AC adapters
=> Don’t rely on USB ports for power when you don't have to. If your USB device has its own AC adapter, use it!
Connect USB drive AC adapters even if "the adapter is supposed to be optional" or "you never had to connect it before"
>> Note: A device LED only indicates the device is getting some power but doesn't mean the device is getting enough power!
Plug-in laptops
Check hardware connectivity for possible points of failure
See How to Check Hardware / Connection Issues with your USB Device
Check if Windows filter drivers may be the problem
=> Bad or corrupt filter drivers can cause CD/DVD, flash and hard disk drives to not work correctly
See CD/DVD or Disk Problems? How to Fix Problems Caused by Filters
Check the USB Storage device driver
=> If no USB storage devices can connect the driver might be disabled (may be a sign of malware)
Connect the USB storage device
Run Serviwin (http://www.nirsoft.net/utils/serviwin.html). Click View->Drivers
Scroll to USBSTOR. Verify StartupType=Manual and Status=Started
If StartupType= Disabled, rt click to change it to Manual. Reboot
Reinstall the USB controllers and motherboard chipset drivers
=> When it appears that your USB ports just aren't working right
How to Reinstall Your USB Controllers and Motherboard Chipset Drivers
Check for Viruses / Malware
=> Malware infections can interfere with USB drive functionality. See
8-step Malware Removal Instructions (http://www.techspot.com/vb/topic58138.html)
Virus removal from USB Drives (http://www.whoismadhur.com/2008/01/26/how-to-remove-virus-from-usb-drives/)
2. Additional Steps when: USB Drive Doesn't Appear in Explorer or My Computer
If the USB drive appears in Device Manager but not in My Computer or Explorer
Check Windows policy settings in the registry
=> Windows may be configured to hide drives from view in Explorer and My Computer (may be a sign of malware)
Click Start->Run, enter regedit to open the Registry Editor
Navigate to key HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explor er
Look for a value named NoDrives. If the key or value doesn't exist, there's nothing being hidden
Otherwise, rt click NoDrives then delete it and reboot to unhide all drives
Fix Drive Letter Conflicts
=> Your USB device may be trying to use a drive letter reserved by a different device or prior installation
Use the DriveCleanup tool (see above) to uninstall then reinstall USB storage devices
3. Additional Steps when: Write Protected, Raw Filesystem, or for General Read/Write Error Messages
Correct filesystem errors
=> If the drive is detected and is assigned a drive letter
Run chkdsk x: /r (http://support.microsoft.com/kb/315265) (where x: is the USB drive letter)
Check if Write Protection enabled
=> If all your USB storage devices appear to be write protected
Click Start->Run, enter: regedit
Navigate to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control
If sub-key StorageDevicePolicies exists, rt click then delete it
=> Also: Closely examine your flash drive. Make sure there's not a write protect switch or tab on it
Data Recovery
=> Download TestDisk and PhotoRec (http://www.cgsecurity.org/wiki/TestDisk_Download) freeware tools. (The one download gives you both)
TestDisk may help recover lost data on corrupt or deleted partitions (click for instructions) (http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step)
PhotoRec focuses on recovering lost Photo and Image files (click for instructions) (http://www.cgsecurity.org/wiki/PhotoRec_Step_By_Step#Run_PhotoRec_executable)
=> A couple "Try then Buy" commercial data recovery tools are listed below. I've never used either but
> I've seen people often (not always) post good results after using the two commercial tools listed below
> The tools will report (for free) the names of the files it can find. You'll need to buy it before it attempts to recover those files
> Note: Finding lost file names is a good start but still doesn't guarantee the results
Partition Table Doctor (http://www.ptdd.com/)
Get Data Back (http://www.runtime.org/data-recovery-faq.htm)
4. Additional Steps when: All Else Fails
Data Recovery
=> If your USB drive is physically damaged it may be impossible for Windows to detect it let alone for s/w tools to recover any data
Flash drives, in particular, are notoriously more prone to physical h/w damage then most people seem to think
In such cases, your best recovery option may be to hire a professional data recovery service. They'll open the drive to attempt recovering data directly from the media
Of course, it's your decision if the recovery $$ cost outweighs losing the data (and please substitute the currency symbol of your choice :) )
Reformat the Drive
=> Reformatting the drive will erase all the data on the drive but may allow you to reuse the drive (if you still trust it!)
=> Click for info (http://www.techspot.com/vb/post687891-2.html) to reformat your drive
