.GRP File Extension
File Type 1StarCraft Graphics Group File
What is a GRP file?
Collection of frame images used for units, weapons, spells, wireframes, and menu graphics within Starcraft; each object may contain anywhere from a few to several hundred frames.
GRP files may be extracted from the .MPQ file. They are referenced by StarCraft, but can be edited with a third-party editor.
File Type 2SmarterMail Group File
.GRP File Association 2
File created by SmarterMail, an email server application used to host Web email access; stores one day's worth of email messages for a mailbox folder; used for storing a database of email messages for a particular user.
GRP files are created with filenames that reflect the date of the email messages. For example, the file 2011-01-01.grp contains all email message data for January 1, 2011 for a particular mailbox folder. GRP files are saved with a corresponding ".cfg" file, which has the list of all email messages and the GRP file where each message is located.
File Type 3Windows Program Manager Group
.GRP File Association 3
Defines a group of programs listed in the Windows Start Menu; i.e. "Main," "Games," "Accessories," or other folder.
If a GRP file becomes corrupt, you can restore it to Windows default settings by using the Program Manager. Select File→Run, then type "setup /p" and press Enter. This will rebuild the GRP file using Windows default settings.
File Type 4Ken Silverman's Build Engine Group File
.GRP File Association 4
A GRP file is a game data file used by games that are built with Ken Silverman's Build Engine. Example games include Duke Nukem 3D and Shadow Warrior. GRP files can store various kinds of game data, such as graphics, audio, and map information. They are saved in a simple uncompressed format and therefore can easily be modified to change gameplay.
The group format is an older format and therefore support for it is limited. There are still tools such as kgroup and kextract which can be used for extracting the contents of the files and for repacking the files with updated content. These programs are part of Ken Silverman's Build Engine.
NOTE: Since there are several branches of Ken Silverman's engine, there may be slight variations in GRP files. Therefore, you should look into the group file format documentation for the specific game you have.