How to Avoid Problems with USB Storage Devices

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[center]How to Avoid Problems with USB Storage Devices
Updated May 2, 2010[/center]
If you're having USB drive problems, also see: Troubleshooting Guide Windows Won't Recognize Your USB Hard Drive

Do's and dont's to avoid problems with USB Storage Devices

  1. Don't: “Surprise” Windows by unexpectedly removing your USB storage device
    => USB storage devices are "hot pluggable". This means you can plug them in any time but does not mean you can simply unplug and/or power them off anytime!
    => !!Never, ever!! unplug a USB storage device before first either stopping the device using Safely Remove Hardware icon or shutting down Windows
    => Unplugging unexpectedly may corrupt your storage device and result in partial or total data loss!!

    The Safely Remove Hardware icon
    You'll find it among the notification area icons along the bottom right of your Windows Desktop

    => Notification Area icons appear on the right side of the Windows Task Bar
    => The Task Bar normally appears along the very bottom of your screen

    The Safely Remove Hardware application informs Windows you intend to remove a device. This gives Windows an opportunity to prepare for the removal by taking steps such as halting data transfers to the device and unloading device drivers. Removing hardware from a running system without using the Safely Remove Hardware application, is referred to as ”surprise removal”

    How to use the Safely Remove Hardware Icon
    Before removing a USB Storage Device
    • Click Safely Remove Hardware icon to see a list of attached devices. Any device on the list should be stopped before you remove it
    • Click the device you want to remove. Only after Windows tells you it's stopped, is it safe to remove it
    • If Windows says "Device can't be stopped" it means you probably still have a window open that's referencing/using the device (e.g. you have an open Explorer windows that's displaying folders and files on the device. This would prevent Windows from closing the device's filesystem and stopping the device for removal)
    • Windows must say the device is stopped before you can safely remove it
  2. Do: Disable Write Caching for USB Storage Devices
    => Surprise removal is a particular concern if write caching is enabled for the USB storage device
    => If the USB device is surprise removed, data loss or corruption might occur

    By default, Windows disables write caching for USB storage devices but it's worthwhile to double check
    • Open Device Manager and look under Disk Drives
    • Select your USB disk drive, click Properties
    • Click Policies tab
    • Click Optimize for quick removal to disable write caching on the storage device
  3. Don't: Allow Windows to Turn Off a USB device to save energy
    => Windows’ Power Management allows Windows to "suspend" your USB devices to save energy
    => But Windows' USB "suspend" mode has long been problematic. (And there’s a long history of hotfixes to prove it!)

    I recommend permanently disabling any sleep mode for your USB disk devices. It may help fix current issues as well as prevent new ones
    >> Caveat for laptop users: Laptops running on the battery may drain a bit more quickly if laptop is idle and USB devices aren’t allowed to “sleep”
    >> Laptop users may choose to enable/disable this feature, as needed, when running off of battery power
  4. Don't: Rely on USB Flash Drives for your Backup or Important Files
    USB Flash drives are very handy and useful but notoriously prone to failure. Don't rely on them to save your important files

  5. Do: Prevent Drive Letter Conflicts
    Windows assigns the “next available” drive letter when a removable storage device (such as USB flash drive, hard drive, card reader, etc) is first installed

    Drive letter conflicts can occur (for example)
    • You plug in a USB drive (it gets assigned a driver letter, let's say F)
    • You later unplug the USB drive and subsequently mount a network drive (Windows may re-assign letter F to the network drive)
    • You replug your USB storage drive but you do don't see it listed in either Explorer or My Computer
    The problem is a drive letter conflict for the letter F. In our example
    => USB device data is created when the USB drive is first installed. This includes the drive letter assignment: F
    => But Windows only deletes the drive's USB data when the drive is un-installed, not when it's simply removed
    => So, when the USB drive is replugged, Windows finds and uses its previously created and still stored device data
    => But its data may tell Windows to still use drive letter F which Windows now finds is already in use by the network drive!

To fix Drive Letter Conflicts
  • For the easiest way to fix drive letter conflicts (and clean up all your old USB storage drivers as well!) see
    ==> [post=727106]How to Cleanup and Remove old USB Mass Storage Drivers[/post]
  • To simply reassign a new drive letter using Disk Management. See [post=720763]How to Fix a Missing/Unassigned Drive Letter[/post]
To avoid Drive Letter Conflicts
  • Modify the drive letter Windows assigns when your device is first installed. You want to make sure it's out-of-range of the next-letter-available assignments.
  • Open Disk Management
    • Find your disk in the Disk List displayed in the lower window pane or
    • Find the disk's current drive letter in the Volume List displayed in the upper window pane
    • Rt click and select Change Drive Letter and Paths
  • Assign a new drive letter. But assign your USB devices a drive letter in the range of P through (which are safely out of range of the “next available” letters Windows might choose on its own for other devices)
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