.AC$ File Extension
File TypeAutoCAD Temporary File
File format categories include Binary, Text, XML, and Zip. The format of this file type has not been determined.
What is an AC$ file?
Temporary file generated by AutoCAD, a 2D/3D drawing and design program; contains information used by various commands, including "UNDO" and "HIDDEN LINES."
AC$ files do not contain any drawing data and only exist when AutoCAD is open. They are automatically deleted when the program is closed.