The File Extensions Database

.CNT File Extension

  • Developer by: Microsoft
  • Category: System Files
  • Format: Text

What is an .CNT file?

.CNT is Help Contents File

Help file used by Windows and Windows applications; stores topics for a Help document (.HLP file) in a plain text format; commonly installed with an application that uses Microsoft Help as the help documentation format.

CNT files can be created with Microsoft Help Workshop, an older program for creating help documentation. Older help documents can be updated to the newer HTML Help Workshop format (.HHC files) using HTML Help Workshop.

NOTE: Do not open unknown CNT files, since there is a known security issue that exploits a buffer overflow condition allowing malicious code to be executed on the computer.

Programs that open Help Contents File
Microsoft HTML Help Workshop

How to solve problems with CNT files

  • Associate the CNT file extension with the correct application. On :
    Windows: Right click on any CNT file and then click "Open with" > "Choose another app". Now select another program and check the box "Always use this app to open *.CNT files". Mac: Right click (or Ctrl-click) the CNT file, then click "Open with" > "Other...". Then choose another program and check the "Always Open With" box. Linux: Right click on the file, and select "Open with" and choose another program. iPhone: Tap the file. If you do not see an app to open the file, then tap Share "Share" and choose an app. Alternatively, save the file. Then open the Files app Files app. There long-press on the file, then release your finger. You will see a black menu bar. Then tap "Share" and select an app. Android: Tap the Settings icon on your smartphone, then tap on the Apps section. There tap the Options icon in the top right-hand corner of the screen to change the default apps.
  • Update your software that should actually open .CNT is Help Contents File. Because only the current version supports the latest CNT file format. Search, therefore, e.g. on the Microsoft manufacturer website after an available .CNT is Help Contents File update.
  • To make sure that your CNT file is not corrupted or virus-infected, get the file again and scan it with antivirus software.