Files with ctt suffix can be typically found as old contact files for Window Live Messenger instant messaging client.

There is one other file type using
the CTT file extension!

empty icon.ctt - LabVIEW control template

Detailed description

Software that open ctt file

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CTT file extension - Windows Live Messenger contact list file

What is ctt file? How to open ctt files?

File type specification:

Settings, options, themes or skins file type icon Settings, options, themes or skins file type

ctt file icon: ctt filetype icon

File extension ctt is most likely best known for its use in Microsoft Windows Live Messenger up to version 4.6 and older for its contacts file format.

CTT is a proprietary file format used by Microsoft software. it contains save list of contacts and groups used by the MSN/Live Messenger instant messaging program in XML format. It is used for exporting and importing of whole contact groups.

A typical *.ctt file looks something like this:

<?xml version="1.0"?>
  <service name=".NET Messenger Service">



Microsoft abandoned the use of CTT format in newer versions. Latest versions of MSN grab contacts directly from social networks / e-mail clients or work with CSV format instead. However, it may be still possible to import .ctt file to latest MSN.

Considering the program was replaced by Skype, this file type is more than obsolete now.

This ctt file type entry was marked as obsolete and no longer supported file format.

This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.

Updated: April 7, 2024

The default software associated to open ctt file:

Windows Live Messenger icon

Microsoft Corporation logoWindows Live Messenger  Microsoft Windows software

Company or developer:
Microsoft Corporation

Windows Live Messenger also known as MSN Live Messenger is instant messaging application developed by Microsoft. Live Messenger supports text chat as well as audio and video callings. It was merged with Skype.

Windows Live Messenger for Mac icon

Microsoft Corporation logoWindows Live Messenger for Mac  Apple macOS / Mac OS X software

Company or developer:
Microsoft Corporation

Windows Live Messenger for Mac allows users to communicate or collaborate on the fly, sharing instant messages, presence information, or files across time zones and locales. You can even make audio or video calls with contacts on the Mac or on Windows.

It was eventually merged with Skype, but previous versions are still available for download as part of Windows Essentials.

Help how to open:

You can import .ctt files by selecting File → Import Contact from a Saved file in the application window.

You can view and edit a .ctt in any text editor.

How to convert:

Because .ctt is a XML based format, there is a way to convert it to CSV format used by the later variants of MSN.

  1. Rename the CTT file extension to XML file extension
  2. Open Microsoft Excel (or any good Spreadsheet program) and open in it the file you have just renamed
  3. Delete the first column (that will leave you with just 1 column of data)
  4. Save the file in CSV format

Find converter to ctt file type:

mtt to ctt

File identification strings:

HEX code: 3C 3F 78 6D 6C 20 76 65 72 73 69 6F 6E 3D 22 31 2E
ASCII code: .?xml.version=

List of software applications associated to the .ctt file extension

Recommended software programs are sorted by OS platform (Windows, macOS, Linux, iOS, Android etc.)
and possible program actions that can be done with the file: like open ctt file, edit ctt file, convert ctt file, view ctt file, play ctt file etc. (if exist software for corresponding action in's database).

Click on the tab below to simply browse between the application actions, to quickly get a list of recommended software, which is able to perform the specified software action, such as opening, editing or converting ctt files.

Software that import ctt file - Windows Live Messenger contact list file

Programs supporting the exension ctt on the main platforms Windows, Mac, Linux or mobile. Click on the link to get more information about listed programs for import ctt file action.

Microsoft Windows:

Apple macOS / Mac OS X:

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