Posted by Guest - Unable To Open Twain Source - Canoscan Lide 25 : I'm getting an error that says unable to open twain source on my canon scanner. I'm currently using a Canon Canoscan LIDE 25 scanner. It worked before but when I connect USB on windows 7 and open canoscan toolbox (or press the scan button on the scanner which opens the same software) it keeps telling me that its unable to acquire twain source. Even when I open microsoft fax or scan software it says it can't find the twain device or scanner (dont remember exact msg on that one).

Guest Says: I would go into your devices under system hardware and uninstall the device driver.  THen redownload from the canon website the correct driver and try again.  Reboot after reinstalling and make sure you have the right driver and 32bit or 64bit for your OS before you install it.  Also, reboot iwth the canon scanner on and plugged into the computer so it recongizes it.

Guest Says: Still doesn't work, newest driver and it says "driver working properly" under the devices.  Same error.

Guest Says: This worked for me, I also found this on the internet and it works because I was getting the same twain error as you: 1) Open explorer and see what your twain_32 path is.  Mine was c:\windows\twain_32\cnql25 for canoscan lide 25

Guest Says: This worked for me, I also found this on the internet and it works because I was getting the same twain error as you: 1) Open explorer and see what your twain_32 path is.  Mine was c:\windows\twain_32\cnql25 for canoscan lide 25 2) Then go to environment variables in the control panel.  You will see it under system - advanced system settings.  Look for the button that says environment variables and click it. 3) In the bottom section under system variables, scroll down to "path" on the left and highlight that line.  Click edit. 4) Now you will see alot of paths separated by semicolons. Go all the way to the right and add to the end a semicolon, then enter c:\windows\twain_32\cnql25  and then click OK so all entries are untouched and you added that at the very end.   5) Click ok all the way out to save and reboot, your scanner will now work fine.

Alexnder Trofivom Says: Thanks! It works! (reboot of system is not needed =)

Guest Says: Guest

Apotter Says: I've seen this "fix" few times now, but I have no PATH variable in the System Variables... and since they are all alphabetically ordered, the only thing that does start with PATH is PATHEXT. Tried creating one and adding the path to the twain driver but to no avail. Before it would just say "No twain device found" now before I get that, it will also say: Cable may be disconnected or the cable may need to be replaced.. something like that, and when I close the popup, the "no twain device found" appears.   I'm with Win7 x64 and the scanner worked fine for the past 2 years, then I had to disconnect it for a couple o weeks, and hasn't worked since. It does scan with VueScan but I don't like the results, and it's not free.

Guest Says: thanks it works

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