You may need to install the Kno2client, or, if it has been installed, you may need to set it as the default program for Kno2 files.
Ensure Kno2client is installed
As an initial step, please verify that the Kno2client or Kno2client for Mac has been successfully installed and configured. Please go to the Support Center > Downloads to select and install the current Kno2client, as shown in the clip below:
Verify Default Program
If you have set Notepad, Adobe Acrobat, or another program as the default program to open Kno2 files, you will not be able to print them, even after downloading and installing the Kno2client. You must change the default program that handles Kno2 files to be the Kno2client.
Verify Default Program - Windows 7
From the computer's Control Panel, select Programs > Default Programs > Associate a file type or protocol with a program > look for .kno2 file type. Notice that its default is Notepad or another program. Highlight the .kno2 file type and select "Change Program". Browse and look for c:\Program Files (x86)\Kno2\Inofile.kno2.client.windows.exe
Set that as the default program and you will now be able to print your file.
Alternatively, from Internet Explorer, choose the Settings Gear in the top right corner > Internet Options > Programs tab > Set Programs > Associate a file type or protocol with a program > look for .kno2 file type. Notice that its default is Notepad or another program. Highlight the .kno2 file type and select "Change Program". Browse and look for c:\Program Files (x86)\Kno2\Inofile.kno2.client.windows.exe
Set that as the default program and you will now be able to print your file.
Verify Default Program - Windows 10
Right-click on the Windows Start button and search for Control Panel, Open the Control Panel > Default Programs > Associate a file type or protocol with a program > Default apps > Default apps by file type > look for .kno2 file type. Notice that its default is Notepad or another program. Click on the incorrect default and select "the Inofile.Kno2.Client.Windows" File Type.
Verify Default Program - Mac
In the Finder, select a file with the format you want to change, right-click on the file and select "Get Info" > drop-down “Open with:” and select the program you would like to open the file > click the Change All button and then choose “Continue.” This will cause all files of that type to open in the new application.