You're here because you have a file that has a file extension ending in .gui. Files with the file extension .gui can only be launched by certain applications. It's possible that .gui files are data files rather than documents or media, which means they're not meant to be viewed at all.

The GUI file extension is associated with the Dr. Explain program. This program is an authoring tool assistant for generating printable “Quick Start” information, windows screenshots, illustrations with annotations and other related help data from a live application. GUI files are employed by this program to hold articles and help topic documents produced with its documentation developer. The Carreta Software Ltd.’s GUI Design Studio and Id Software, Inc.’s Doom 3 computer game are programs that also utilize GUI file format. GUI Design Studio is a program that opens and creates GUI files. It’s a design tool with graphical user interface attributes that can automatically display windows and screens linked together to create workflow storyboard samples or models for Desktop, Web and Mobile software applications. GUI files are utilized by this application as document files that contain completed projects and other reference information. Doom 3 is a sci-fi horror game that simulates first person shooter point of view. The game utilizes GUI files to enable game’s Heads Up Display or HUD which shows information about the player’s current weapon ammunition, PDA, video disk and player’s health status.

Launch a .gui file, or any other file on your PC, by double-clicking it. If your file associations are set up correctly, the application that's meant to open your .gui file will open it. It's possible you may need to download or purchase the correct application. It's also possible that you have the correct application on your PC, but .gui files aren't yet associated with it. In this case, when you try to open a .gui file, you can tell Windows which application is the correct one for that file. From then on, opening a  .gui file will open the correct application. Click here to fix .gui file association errors

Be careful not to rename the extension on .gui files, or any other files. This will not change the file type. Only special conversion software can change a file from one file type to another.

A file extension is the set of three or four characters at the end of a filename; in this case, .gui. File extensions tell you what type of file it is, and tell Windows what programs can open it. Windows often associates a default program to each file extension, so that when you double-click the file, the program launches automatically. When that program is no longer on your PC, you can sometimes get an error when you try to open the associated file.