imageCLASS MF743Cdw, MF Scan Utility not work, Scangear will not open

[Gerald2]

My ImageClass MF743CDW Printer scanner isn't working with MF Scan Utility. I can start the MF Scan Utility, but when I click on "Document", the additional icon appears in the taskbar for about 5 seconds, then goes away. The scanner bar does not appear. Also, when I click on "scangear", the same thing happens. The additional icon appears in the taskbar for a few seconds, then goes away. Scangear will not open. This continued for about 3/4 year. Then I made a brand new user on my computer, and it all worked perfectly on the new user. About a month later, it stopped working exactly the same way on that user as it didn't work on the first user. So I created another new user on my pc, and here it works on that new user, but not on the two users from before. I don't want to keep creating new users every couple of months. I have deleted all Canon software and drivers and reinstalled the Canon software from the Canon support website many times. I have stopped and started the scanner in device manager. I was on with Canon support for probably an hour, and came up with nothing. I have done everything I can think of or find online. Also, i recently installed the scan software NAPS2 to try something else since MF Scan Utility wasn't working. On the user that the MF Scan Utility does not work, the MF743Cdw scanner does work on NAPS2 if i use the WIA driver, but NAPS2 does not work if i use the TWAIN driver. If I log in on the newest user that MF Scan Utility does work, NAPS2 works with both the WIA driver and the TWAIN driver. I use Windows 11, it is on 2025H2. I also use Malwarebytes. I use a wired ethernet network for both the PC and the MF743Cdw. I can ping the MF743Cdw IP address from command prompt. 

[shadowsports]

Greetings,

Based on the results, something in your software environment appears to be blocking the Canon software software from running.  It could be your malwarebytes or some type.of operating system corruption.  It seems you can consistently reproduce the behavior by creating new user profiles which I agree is not realistic or sustainable.  I cannot say why it works intermittently after you create a new user account and then stops.  The problem however, is with the software, environment or computer and not with your Canon product or its software.

I know you can temporarily disable malwarebytes.  I think I would go a step further and remove it from my system while testing.  Make sure you restart after it's removed and re-test.  If you find that it's the cause, you can set exceptions for individual software applications in it's real-time protection.  

I'm using the MF scan utility and scangear on four of the seven computers in my house and none have this issue.  I don't use malwarebytes though.  

If removing malwarebytes doesn't resolve the issue then you may need to check the integrity of your operating system installation.  This goes beyond the scope of the forum. 

Other things that come to mind: 

The Canon saw for us to be installed under a user account with administrative privileges. 

You can use system file checker to verify operating system integrity.  sfc /scan now

If problems are found, you can run the dism tool to repair or replace any corrupt files.

Consider running a check disk on your C drive.  chkdsk

Perform a repair install keeping your existing apps and files.  Hopefully however, you can figure out what it is without having to consider more extreme steps. 

[Gerald2]

Thanks for the suggestions. I had disabled Malwarebytes. After your suggestions, I uninstalled Malwarebytes and turned off Windows Defender and Virus Protection. I uninstalled all Canon software and drivers. Then restarted my PC. Downloaded and installed the recommended software for the printer from Canon. And got exactly the same results. It all works on the new user, and doesn't work on the old users. Also ran sfc/scannow and it didn't find any issues.

[Gerald2 · Accepted solution]

I have corrected the problem. In Control Panel, System and Security, System, Advanced System Settings, Environment Variables, System Variables, choose "Path", and "Edit", and "New", and add C:\Windows\twain_32\MF741C_***********   (the folder of the TWAIN driver for the printer), and then I moved the path up a few lines. Now it works.