Getting “unknown error” with Plustek OpticFilm scanners (Windows only)

If you are experiencing getting a message “unknown error” shown in the SilverFast progress status, we suggest to disable the “QuickScan” software running in the background. 
This is either done by using the keyboard shortcut WIN+X, select “Task Manager“.

Click the task manager’s icon for the tab to display the apps to run on Windows startup, locate “QuickScan” in the list, right-click and disable. 

Alternatively, you can use WIN+S, search for “Startup”, open that settings option, and change the mode for QuickScan to “Off“. 

More info on how to do configure startup apps is provided by Microsoft on: 

https://support.microsoft.com/en-us/windows/configure-startup-applications-in-windows-115a420a-0bff-4a6f-90e0-1934c844e473

To complete the configuration, reboot your computer. 

This problem only occurs on and correspondingly the fix only applies to Microsoft Windows operating systems. 

The cause for it is assumed to be a driver interference. 

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Updated on June 9, 2026