Scanner drivers not appearing in list
Posted by Sinclair Hughes, Last modified by Sinclair Hughes on 11 March 2015 04:33 PM

The scanning process uses a TWAIN driver to correspond with the scanner.  If the TWAIN driver is not installed or not available, the scanning process will either not work correctly or not work at all.  WIA drivers may work but will not support all of the scanning functions (eg. no duplex option)

If the scanning is not working

  1. Check that the TWAIN drivers hve been installed.   
    1. Go to Control Panel -> Devices & Printers
    2. Right-mouse-click on the scanner and select Properties
    3. Check to see if the scanner has been installed.
      Alternatively, in Explorer, the TWAIN_32 directory should be off the Windows directory
    4. Download and install the latest TWAIN drivers for the scanner from the manufacturers web site.

  2. Check the TWAIN drivers are available to the user in the Terminal Server environment
    Be aware that USB scanners may require special scanning applications such as RemoteScan or TSScan
    1. Using Explorer, go to the \Windows directory in the Users profile a check to see if there is a TWAIN_32 directory
    2. Under the TWAIN_32 directory check that the scanner's twain drivers are there
      e.g. C:\Users\UserA\Windows\Twain_32\RemoteScan

  3. Check that some other application does not have control of the TWAIN driver
    1. Go to Control Panel -> Devices & Printers
    2. Right-mouse-click on the scanner and select Properties
    3. Select the Events tab
    4. Choose the option to 'Disable' or 'Take no Action' 

  4. Log out of Windows and log in again using a different account.  Try using an Administrator account.

  5. The Twain control calls the twain_32.dll which is the twain data source manager.  Make sure you can find this file when logged in as the User and that they have Read permissions.

  6. Download and run the TWACK diagnostic tool from
    64 bit
    32 bit
    Use this tool to diagnose the problem

If the scanner is still not appearing in the Source list perform some troubleshooting using a third-party scanning application.

  • Download this file, extract and run the dwgdemo.exe application to test the availabilty and functionality of TWAIN drivers
  • Run a file calle 'Imageman Test Program.exe' found in the \spmwin directory
  • Doownload and run a graphics program called  Irfanview

 In some instances we have found that creating a TWAIN32 directory off Windows, then copying the contents of the TWAIN_32 directory will enable the drivers to be found.