DIAGCAB File Extension

Have a problem opening a .DIAGCAB file? We collect information about file formats and can explain what DIAGCAB files are. Additionally we recommend software suitable for opening or converting such files.

What is the .DIAGCAB file type?

The wordy .diagcab extension associates with the Microsoft Diagnostics Cabinet (DIAGCAB) file type. Intended as automated troubleshooting packages to diagnose and/or resolve known issues, DIAGCAB files are part of the Windows Troubleshooting Platform (WTP). DIAGCAB packages are usually offered by Microsoft and other vendors (mainly, OEM) and can often be found on the Microsoft's Fix it online service.

A .diagcab file is a Microsoft Cabinet (CAB) compressed archive that contains a diagnostics package control file (XML, .diagpkg), along with a set of other supporting files (.ps1, .dll, .cat).

The DIAGCAB file type is pre-associated with the Microsoft Support Diagnostic Tool (MSDT, WTP Wizard, "msdt.exe") which is run when a .diagcab file is double-clicked upon. Quite often, the default association is either missing or broken, leading to much confusion around Microsoft Fix it (.diagcab) files. In that case, a .diagcab file can be opened via command line ("cmd.exe") with the following command: "msdt.exe /cab [path_to_diagcab_file]".

Additionally, any .diagcab file can be treated as a regular CAB archive.

Software to open or convert DIAGCAB files

You can open DIAGCAB files with the following programs: 

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