CLSID file format description

Many people share .clsid files without attaching instructions on how to use it. Yet it isn’t evident for everyone which program a .clsid file can be edited, converted or printed with. On this page, we try to provide assistance for handling .clsid files.

1 filename extension(s) found in our database.

.clsid - CLSID Identifier Data

The CLSID data files are related to Microsoft Windows. The CLSID file is a CLSID Identifier Data. A CLSID is a globally unique identifier that identifies a COM class object.

Microsoft Windows
Data files
- / -
CLSID Identifier Data related extensions:
SpaceCAD Rocket Model
Celestia Star Catalog
OS/2 Warp REXX Script
DIALux Luminaire Data
FreeSurfer Annotation
LabQuest Results Data

Naturally, other applications may also use the .clsid file extension. Even harmful programs can create .clsid files. Be especially cautious with .clsid files coming from an unknown source!

Can't open a .clsid file?

When you double-click a file to open it, Windows examines the filename extension. If Windows recognizes the filename extension, it opens the file in the program that is associated with that filename extension. When Windows does not recognize a filename extension, you receive the following message:

Windows can't open this file:


To open this file, Windows needs to know what program you want to use to open it. Windows can go online to look it up automatically, or you can manually select one from a list of programs that are installed on your computer.

To avoid this error, you need to set the file association correctly.

Operating systems currently supports the following operating systems:

Windows XP/Vista, Windows 7/8/10, Windows 11, CentOS, Debian GNU/Linux, Ubuntu Linux, FreeBSD, macOS, Mac OS X, iOS, Android

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