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Unable to Access Removable Drives after Installing Image for Windows when Acronis Software is Already Installed


Installing Image for Windows when Acronis software is already installed, results in one or more of the following problems when using removable drives:

  • Drive is not shown in Explorer.

  • Drive is shown in Disk Management, but no drive letter is assigned. Manually assigning a drive letter may allow other programs to access the drive, but the drive is still not shown in Explorer.

  • Image for Windows and True Image can see the drive, but no drive letter is associated with it.

  • Drive is shown in Disk Management, but the status is reported as No Media.

  • Disk Management may fail to start due to an error.

  • Disk Management may hang when scanning disks.

  • Safely Remove Hardware shows the drive, but only shows the name (no drive letter).

Acronis software includes (but is not limited to) the following:

  • True Image
  • Backup and Security
  • Disk Director
  • Seagate's DiscWizard (based on True Image)
  • True Image WD Edition

These problems can occur on Windows XP and Windows Vista. This problem should not normally occur in Windows 7 if Image for Windows 2.54 or later is used and the Acronis software installed supports Windows 7. Installing Acronis software in Windows 7 that doesn't support Windows 7 may cause this problem and is not recommended.

While any type of removable drive may be affected, the following types are the most common: USB flashdrives, USB hard drives, ZIP drives, FireWire drives, and eSATA drives.


The Acronis snapman driver is causing problems with other filter drivers (including PHYLock and PartMgr). Older versions of the snapman driver block Image for Windows from communicating with PHYLock and therefore the Image for Windows installer ensures snapman is not between Image for Windows and PHYLock. However, newer versions of the snapman driver are not properly copying down the device characteristics from the lower driver and may still be blocking certain IOCTLS which prevents PartMgr from knowing the proper drive type and hense the various problems listed above.


In most cases, the problem can be solved by doing one of the following:

  • Uninstall the Acronis software. This is the best option.

  • Uninstall the Acronis software, reboot the computer, then reinstall the Acronis software. Doing this places the snapman driver after PartMgr in the list of filter drivers. This is an option if you wish to continue using the Acronis software along with Image for Windows.

  • Manually edit the UpperFilters registry key and place the list of filter drivers into an order that allows them to function correctly. If you are not comfortable making registry changes, using this method is not recommended.

    Note: If done incorrectly, the following changes can result in the computer failing to boot into Windows. You may wish to create a Restore Point or backup image before continuing.

    1. Start the Registry Editor. This can be done by pressing Windows Key + R to open the Run window. Type in regedit and click OK. If running Windows Vista or Windows 7 with UAC enabled, click Continue or Yes to allow the program to run.

    2. Browse to the following registry key:

    3. On the right side of the window, you'll see the list of values for the key. One of these values is UpperFilters. This value contains the list of drivers, including snapman and phylock.

    4. Right-click on UpperFilters and select Modify... from the pop-up menu.

    5. Reorder the list of filter drivers as required to allow them to function correctly. When finished, click OK to save the changes and then restart Windows.

      Keep in mind the following: phylock must be listed before PartMgr. Also, snapman will need to either be listed before phylock or after PartMgr, depending on the version of Acronis software being used (see below).

      Older versions of the snapman driver will need to be placed before phylock so it doesn't block IOCTLS and prevent Image for Windows from communicating with PHYLock. This usually includes the snapman driver used with older versions of True Image (version 6, 7, 8, and possibly the early builds of 9).

      Newer versions of the snapman driver need to be placed after PartMgr to avoid problems with PartMgr. This includes the snapman driver used with the more current versions of True Image (version 9, 10, 11, 2009, and 2010). Note: Some versions of the snapman driver in this category include a number with the name. For example, the driver may be named snapman380 instead of snapman.

      Here is an example of what the UpperFilters value looks like in Windows XP when True Image 2009 (build 9,809) is installed followed by Image for Windows 2.54:
      tdrpman251 snapman phylock partmgr

      In this case, the change would be:
      tdrpman251 phylock partmgr snapman

      Note: The above example is just that, an example.

      Using this method doesn't require uninstalling and reinstalling the Acronis software and may therefore be the easiest solution, especially if multiple Acronis programs are installed.


Technical Notes:

Be aware that until there is a proper and stable working version of the Acronis filter drivers, that because of the many different versions/builds of Acronis software, the multiple versions of the snapman driver, and the various installation methods used by Acronis, it's possible that a working system may develop problems after installing Acronis updates or upgrades.

If you are planning on installing current versions of both Image for Windows and Acronis software, it's recommended to install Image for Windows first and use it prior to installing any Acronis software.

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