"Could not write to the file." Appears When Scanning - MF Toolbox (Windows)

Article ID: ART169531 | Date published: 02/15/2018 | Date last updated: 02/15/2018


MF Toolbox error Could not write to the file.



If you receive an error similar to this when attempting to scan with the MF Toolbox:

This may be caused by a setting in Windows Defender called Controlled folder access.  If this is enabled, it will prevent you from being able to scan with MF Toolbox.

There are two ways that this issue can be resolved.

The first way to resolve this is to turn off Controlled folder access in Windows 10.

The second way to resolve this is to allow Canon MF Toolbox to work through the Controlled folder access feature of Windows Defender.  Click here for instructions.

Follow the steps below to turn off Controlled folder access.
  1. Open the Windows Defender Security Center by either clicking the Windows Defender icon in the System Tray, or by going to Settings -> Update & Security -> Windows Defender and clicking Open Windows Defender Security Center.
  2. Click Virus & threat protection.

  3. Click Virus & threat protection settings.

  4. Scroll down to Controlled folder access.  If it is On, click it to turn it Off.

    If you are prompted to grant permission to turn this function off, click Yes.
  5. Controlled folder access will now be turned off.

Scanning can now be performed.

Return to top

If you do not wish to turn off Controlled folder access, you can add MF Toolbox to the list of apps that can work through this feature.  Follow steps 1 through 3 listed above.  After scrolling down to Controlled folder access, click Allow an app through Controlled folder access.  Click the plus sign next to Add an allowed app.  In the window that appears, navigate to C:\Program Files (x86)\Canon\MF Toolbox ver4.9 and double click MFTBOX.exe.  It will show in the list of allowed apps:

If MF Toolbox was opened when you added it through Controlled folder access, close and re-launch it.  You should now be able to scan.


Rate this Article
Was this article helpful?
Yes, This document is helpful
No, This document needs a clearer explanation
Please provide your comments