MDMP, Windows Minidump File (.mdmp)
The MDMP System file format
On Windows computers, when a program throws an error or crashes, an MDMP file is created by the operating system. MDMP files are made up of compressed data that are comprised of a data dump from the crashed program's memory. This includes debugging information about the error or crash as well. While MDMP files are compressed files, an uncompressed version is also created alongside the MDMP file. It uses the file format extension HDMP. The MDMP file can, in severe cases, also be sent to Microsoft directly in order to create a bug report and provide further information about the program crash.
Technical details of MDMP files
If you have Microsoft Visual Studio installed, you can analyze the MDMP file yourself. To do so, navigate to File > Open > Project. When selecting "Dump Files" as the type of files displayed, you can choose your MDMP file for opening and run the debugger. The information on the file will run through the debugger and give information about the instance responsible for the crash of the program in question.