Canon Scanner
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Canon Scanner Problem (Windows XP):

FIX for "Unable to select TWAIN source"

The following information was put together after experiencing the above problem and numerous communications with Canon support, culminating in Canon finally giving up and sending me notification that they could no longer provide support! After much research on the 'net I solved the Canon scanner problem and decided to put all the info together for the potential benefit of others. I suggest reading the whole article first before proceeding...

Ensure that the correct version of the CanoScan Toolbox & Scangear CS is installed (for Windows XP).

http://software.canon-europe.com/products/0000465.asp

The following (January 2010) Canon scanner software needs to be installed to use your LIDE20 and the Canon Toolbox with Windows XP:

ScanGear CS (7.0.3.1a)
CanoScan Toolbox (4.1.3.5)

Note: I used the VueScan application for scanning whilst trying to resolve the Canon Toolbox problem. Vuescan does not use TWAIN

If the problem persists, manually remove the scanner and driver from the computer using the procedure below.

  1. Connect the scanner to the computer.
     

  2. Open the Device Manager (via System in the Control Panel).
     

  3. Look for the Imaging Devices entry and expand them by left clicking on the box with a plus sign. Right click on the entry for the scanner and select the Remove / Uninstall option. When removed, disconnect the scanner.
     

  4. Click START/ALL PROGRAMS. Find the entry for the scanner /driver and select the uninstall option.
     

  5. Navigate to C: WINDOWS/TWAIN_32 folder. Locate the entry for the scanner and delete it (will show as CNQL�.).
     

  6. (Care is required here, so that only the correct file is removed).

Navigate to C: WINDOWS/INF.

If the INF folder does not appear, click on the View tab at the top and then Folder Options. Click on the View tab. Underneath, where the Hidden Files folder appears, select the Show All Files option. Click Apply, then OK. The INF folder will now display.

Look for �OEM� files. Each OEM file has a number and most are in pairs (e.g. OEM1.inf and OEM1.pnf). Starting with the highest number and one at a time, open each OEM.inf file and make a note whether a reference to �CanoScan / CNQL �USB set up file for�� (or very similar wording) appears on the top line.

Once all files have been checked, delete the OEM.inf and accompanying OEM.pnf files which refer only to CanoScan USB CNQL�USB set up file for�� (or very similar wording).

  1. Open the C: Drive. Locate and delete the Canoscan folder.
     

  2. Restart the computer.
     

  3. Re-Install the Scangear driver and also the Canoscan Toolbox downloaded from the Canon website.
     

  4. Connect the scanner to the computer. The driver installation will complete.

If the scanner will still not communicate (via the Toolbox or another application), try installing on a different computer (if possible), to rule out a fault with the scanner itself. The scanner should be connected directly to the computer.

  1. Use of a USB Hub is not recommended.
  2. Other connected USB devices (except mouse or keyboard) may interfere with the communication.

  1. Still no luck! Check the PATH variable�

C:\WINDOWS\twain_32\CNQLxx (xx is the number of your scanner) should be included in the PATH environmental variable.

To change your PATH variable go to Control Panel->System->Advanced->Environment Variables and then select Path from the System Variables window. Recommend you copy the whole path statement and put it into a temporary Wordpad document and then edit it there. This way you can see the whole statement and it is much easier to work with, also, often there may be some duplicate entries and so you can use it as an opportunity to clean the statement up as well. Copy and paste the amended entry back to where you got it from.

  1. Following the above procedures did not fix the problem so I complied with the following:

In the C:\Documents&Settings\username\Local Settings\Temp folder,
there are 4 files relating to Twain.
Twain001.mtx (I found my file set to Read only!)
Twunk001.mtx
Twunk002.mtx
Twain.log

By deleting the Twain001.mtx file, I initially renamed it Twain001.mty, scanning should be restored, IMMEDIATELY and the file re-created automatically. It is a small file, 1 to 4 KB. When viewed in Notepad, when the scanner is working, it always contains a number like 5 or 29. When viewed and the scanner is NOT working, it always contains letters such as zzzz or DDDD, and the Twain.log file reports: "atol FAILED".

This did the trick, scanner now works perfectly.

 




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This page was last updated on Saturday, April 21, 2012 13:53 by Richard Spencer.