A member on wordpress named GeeZee did not have success with the below solution but the issue was related. First uninstall any previous print drivers (including canon). Navigate to your c:\windows folder and there should be a folder named twain, or twain_32. Navigate into this folder and delete any contents. Install the canon drivers and you should be all set. Thanks GeeZee for the info
Someone I know recently just purchased a MX340 Multi Functional Printer. Setting up wireless was a pain, and the scanning portion was even more so. The scanning function did not work.
Anyways I’m just going to focus on the scan portion right now. Whenever I ran the navigator application it looked like nothing happened. Task Manager showed that the navigator application was using a huge chunk of process time. If I tried to hit the scan button on the multi functional printer the same thing happened. After digging around, running a file monitoring program, I managed to figure out the issue. More specifically it was a permission issue.
Follow the steps below and hopefully this will fix the problem if you have similiar results:
- Hit Ctrl+Shift+Esc to run Windows Task Manager. Close all mpnex31.exe items if listed.
- Navigate to c:\windows
- Right click twain.dll and goto properties
- Click the security tab, then the Advanced button.
- Click the Owner tab and click “Edit…”
- Select your username and click apply.
- Click OK, Click OK.
- Click the EDIT button under premissions.
- Select the username SYSTEM and allow everything.
- Select your username and allow everything.
- Click APPLY then OK.
- Follow the above steps but for the file twain_32.dll file
After that you should be able to run the navigator program.
I tried to contact Canon that I found a fix but they didn’t reply. So if somone from Canon reads this can I at least get a thank you? Or maybe even compensated for the amount of debugging work I had to do?
Inside the mind of Justin 
I have exactly the same problem with my new Canon Pixma MX870. I have a Dell pc running on Win7. Called Cannon’s tech support. After much back and forth the conclusion was twain driver is in use by Dell service. They told me to talk to Dell support. Easier said than done. I was excited to find your solution. Unfortunately it didn’t work for me. No change.
Hey Geezee. Thanks for the feedback. If I do recall correctly the system I worked on also had a Dell printer installed before. If you don�t mind can you run mp naviagator, let it run for 10 seconds or so, end the process in task manager, and then send me the contents in the file:
c:\users\your_username\AppData\Local\Temp\TWAIN.log
Please replace �your_username� with your login name for windows. I believe when the problem occured over here the file mentioned something about a execution error for a function in twain or something.
I have not tested this out but a fix might be to double check to see if the old dell software has been removed (as well as the canon software). If so, try making a backup of twain.dll and twain_32.dll to the desktop, delete the copies in your windows folder and re-run the canon install software. If that does not work copy the files back from the desktop to the windows folder so the system is in it’s original state. Let me know how things go!
I had a useless tel chat with Dell tech support. They wanted $60 for consultation. I said thanks but no thanks. Called Canon again. This time they found a solution. I had a Dell folder inside twain_32 that was causing the problem. After I cut it to desktop I was at last able to open Canon MP Navigator and start scanning. What a relief. But thanks for trying to help anyway.
Awesome, I’ll add the info to the top of the post. Thanks for letting me know!
Many thanks! Had the same problem. Changing the permissions on the dll’s did not solve it, but Geezee’s tip did. Google led me here, would not have found this solution myself. Again, many thanks!
I had exactly the same problem with the Canon MG5250 on Windows 7 64bit. Changing the permission of the dll and deleting the folder Lexmark solve it. Thanks a lot
No problem. Glad to hear this page is helping people out =).
Unbelievable, thank you so much! I have a Canon Mx870 , Dell Latitude 6410 running Window 2007 64 bit. Could not get MP Navigator EX 3.1 to open. DId exactly what others did here, changed ownership of the .dll and it didn’t fix the problem. But I just deleted the Dell folder from the Twain folder and success. Thank you so much. I have spent many frustratinmg hours trying to get scanning to work. I would never have figured this out.
OMG it actually worked for me too! Thanks a lot! This is ridiculous, my canon MG6100 still had this problem, though it was released recently.
Thank you very much for this post. Helped me out after 6 months of not being able to scan. Also had an old Dell folder in the twain folder that I deleted based on your (Geezee’s) suggestion to delete everything but the latest Canon drivers from the folder. Did the permissions and the deletion at the same time (couldn’t delete without changing the permissions).
Thanks worked for me as well, after3 days of pulling my air out trying everything else. Canon support were not much help on this occasion.
I was trying to install a Canon MG 250 on a Windows 7, x64 pc but the scanner and the software wouldn’t work.
Thanks again!
Thank you as well. After two years (and giving up on trying to fix the problem) deleting the Dell folder did the trick. Appreciate the time you put into figuring this out.
Thank you very much for the solution. I have a Canon MG5250. By deleting the Dell folder in the twain_32 folder using Unlocker, the problem was solved.
You guys are awesome! Fixed the problem! It seems like Dell should have an uninstaller for their Dell All-in-One software, but they don’t!
After changing the permissions, I am still unable to delete the Dell folder in the twain_32 folder. A pop-up window informs me that the file is in use ! Huh ? Rebooted, with no change. How is it in use? Any suggestions? Thanks.
Hey there. Did you uninstall the Dell printer software?
You could use a program called process explorer to find out which program id using the file and then delete it.
Alternatively, while the computer is booting up you can continuously press f8. Select the option to boot into safemode and try the steps again. Be advised since the file is in use, a program is using the file and new problems may occur if that program is not removed. Instead of deleting the dell folder entirely, copy the dell folder to your desktop, and then delete it from the twain folder. If you run into any issues, copy the dell folder back.
Hello Justin, thanks for your response.
Yes, I deleted the old Dell printer software. I copied the problematic Dell folder onto my desktop, but cannot delete it from windows/twain_32 folder because the “folder/file is open in another program”. So, I downloaded Process Explorer, as you suggested, and discovered that the program id that is using the ‘dlbttwds.ds’ file is Lexmark Twain Data Sourse (is Lexmark part of Canon???). The only printer connected to this computer is the new Canon MX series printer associated with this problem. The process id for the ‘dlbttwds.ds’ file is CNSEMAIN.EXE type DLL = Canon Solution Menu EX. I do not wish to delete this file during boot into safemode since it may affect my Canon printer.
Hey there, lets try one more thing.
First, make sure you do have copy of the folder that dlbttwds.ds is in.
Next, launch process explorer and terminate the process using dlbttwds.ds. You should be able to delete the file now.
Restart the canon program and hopefully it will work. If it doesn’t, copy the folder back.
I can try to do a quick remote session to fix the issue if this does not fix the issue.
Good Luck!
i have clicked ctrl+shift+esc all at the same time to open up windows task manager but i don’t know how to navigate to c:/windows or were to find it
Hi there. Open up the windows “run” window. A quick way to do it is by pressing the windows key and R at the same time. Optionally it should be somewhere under the start menu. When the window pops up type in
c:\windows
and click ok
i have double clicked mp navigator, it asks for my permission then doesn’t do anything, after i click “yes” nothing changes, no program opens
Had similar problems with win7 and Canon Pixma 5350 but this fixed it (after endless wasted hours)
Use the System File Checker tool (SFC.exe) to determine which file is causing the issue, and then replace the file. To do this, follow these steps:
Open an elevated command prompt. To do this, click Start, click All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator. If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.
At the command prompt, type the following command, and then press ENTER:
sfc /scannow
The sfc /scannow command scans all protected system files and replaces incorrect versions with correct Microsoft versions.
For those can’t delete files and folders I use Unlocker. It works.
Thank y’all so much! This post is STILL helping folks out years later! My Pixma MG6120 just would not scan to Win7x64 and Canon was no help at all! After months of trying to figure this out, you finally saved me! Thanks again!
Thank you!!!
Thank you for your solution. The deleting of other twain-files solved my problem on a Dell Inspiron 1750 with a Canon MG5350, but the main problem was a older photo scanner with Silverfast twain-plugin. I removed this and MP navigator EX 5.0 works.
Still working years later. Thanks for the post!
It worked for me today with W7 (32bit) and Canon LIDE110. I just cleared the Twain32 folder.
Thanks a lot. It works!!
Phew. I thought I was going to lose the little bit of hair I have left.
For the record, I’m running Windows 8.1 with a Canon MG5220.
If anybody comes across this problem, make sure to delete all of the contents of the twain_32 folder. You may have to change the permissions/ownership of the file(s) within this so that you can delete them. In my case, the file was wiatwain.ds and I had to change ownership of this file to my computer account name before I could delete it. After I deleted this, I ran the latest MP drivers installer and noticed that the installer create two subfolders (prefixed with MG5200 series) in the twain_32 that contain the USB- and network-connected files required to use the scanner function.
I really cannot believe that Canon does not have this documented somewhere.
Hope this helps others.
I would like to thank Justin and everyone else on this thread. I had a similar problem to Wayne and using a combination of methods suggested by Wayne and Justin…and also everyone else’s suggestions…I somehow managed to get the Canon Navigator software to finally start. I had to delete an old Dell printer file using safe mode that was located in the twain__32 folder. I also had to give full permission to the system in the twain dll folder. I really had no idea what I was doing, but just going on intuition and the steps Wayne and Justin helped me out. Canon support just told me to use paint to scan which does work, but this is better. Thank you. Solution still working in 2014. Jean
Glad to help =)
Hi. I hope you are able to read and reply to this message. Whenever I open my MP Navigator EX 5.0, this message keeps on showing up.
Cannot start the MP Navigator EX. Check the following points.
1. The supported model of this software is as follows. Check your product model is listed.
Canon MG3100 series
When your product model is not listed, install correspondent MP Navigator or MP Navigator EX.
2. MP driver/scanner driver which supports your product model is installed.
3. Your product model is connected to PC properly and the power is ON, if there is a power supply.
4. Reconnect the USB cable when connected with USB.
My model is Canon MG3100 series.
It is connected to the PC properly.
The power is ON.
I already did the reconnecting.
I think it’s because the installation went like this. At first, nothing was working. A window popped up saying No MP Drivers are installed correctly and I have to reinstall them. I did this over and over with the same result. What I did is I went to the My Printer application, and clicked Diagnose and Repair Printer. It all worked out okay, with all the Canon Solution Menu EX buttons and options appearing. EXCEPT for the Use Scanner one.
I did what you mentioned in this post but nothing’s working. Could you please help?
If MP crash after scanning on windows 7, check if you have install SMART Notebook application with drivers, dont know why, but this program add some file (probably camera driver) into twain32 file (C:/Windows/Twain32) . After unnistalling SMART app, scanning works. Maybe you just could delete that corrupted file, but on own risk!
Unfortunately this fix didn’t work for me. I have Win7 and did a fresh install. No previous installs for printers/scanners.
Cannon, you suck. Fix your products!