File Extension Library


.UNDEFINED File Extension

  • Category: Various data Files

What is an .UNDEFINED file?

.UNDEFINED file extension has been classified as Various data Files.

.UNDEFINED is Undefined file

The undefined file extension is sometimes used by programs to label files whose origin or purpose is not clear. These can be for example generated by file recovery systems that fail to recognize the file formats.


How to open:

It may be possible that some undefined files can be only accessed with the program that generated them.

How to convert:

Perhaps some undefine files may be converted, but we do not know about any such conversion at this time.

How to Open .UNDEFINED file on different platforms

Open .UNDEFINED File on Windows

  • Right-click a .UNDEFINED
  • Left-click "Open With" > "Choose another app"
  • Select the program that opens .UNDEFINED file and Select check box "Always use this app to open .UNDEFINED files" Press "Ok"

Open .UNDEFINED File on Mac

  • Right-click (or Ctrl + Left-click) the .UNDEFINED file
  • Click "Open With" > "Other.."
  • Then choose another program from the app list and press "Open"
  • Select check box "Turn on" for "Always open in app"

Open .UNDEFINED File on Linux

Right click on the .UNDEFINED file, choose "Open with" and select a program from the list above

Open .UNDEFINED File on iPhone

Select a file. If you don't see an application to open the .UNDEFINED file, tap "Share" and choose the right app.
Method 2
Save the file. Then open the app «Files». Touch and hold the file, then release your finger. You will see a black menu bar. After that tap "Share" and select an application.

Open .UNDEFINED File on Android

Tap the Settings icon on an Android smartphone, then select «Applications». Click the Settings icon in the upper right corner of the screen, to change the default apps.
If you want to open, edit, save or even convert .UNDEFINED files on Android, then your best bet is to download one of the dedicated apps available on Google Play.

How to fix problems with .UNDEFINED files

  1. You need to update the application that you normally use to open .UNDEFINED files. Only the latest version of the software supports the current .UNDEFINED file format
  2. You need to check the .UNDEFINED file for viruses. To do this, you need to scan it with a popular antivirus (Norton, Nod32, Kaspersky, Dr.Web, etc.)