HDMP is an acronym for Windows Heap Dump file. HDMP is an uncompressed version of an error dump originally generated in Windows XP/Vista. Windows XP/Vista generate this file when either a program delivers error or gets crashed. The .HDMP file extension keeps a dump of the program state about the point when the issue occurred. These HDMP files get created for the purpose of analyzing or investigating the reason that made the application get crash.