.STEAMSTART File Extension
File TypeValve Steam Start File
This file is saved in a binary format, which requires a specific program to read its contents.
What is an STEAMSTART file?
Temporary file created for games downloaded by Valve's Steam game distribution service; named by a game filename, an identifier, and the ".steamstart" suffix (e.g., game.exe.1234.steamstart); sometimes created when games do not load properly.