What is a .mdmp file?

About the format

An .mdmp file (often just named .dmp) is a user-mode minidump: a record of one program crashing, written by Windows Error Reporting, Task Manager, Visual Studio or tools like procdump. It starts with the four bytes MDMP and contains a directory of streams — system information, the exception that killed the process, the list of loaded modules, and (depending on the capture options) thread stacks and memory. For an end user the useful part is small: which program crashed, which module the crash address falls in, and the exception code (0xC0000005 means a memory access violation, by far the most common). For developers, the same file opened in Visual Studio or WinDbg with matching symbols reconstructs the full stack trace. Crucially, this is NOT the blue-screen dump format — kernel dumps from C:\Windows\Minidump use the PAGEDU64 layout instead, and each kind needs its own reader.

How to open a .mdmp file

Is a .mdmp file dangerous?

Not executable. Like all memory captures it can embed pieces of the crashed program's data, so avoid posting dumps of programs that handle passwords or personal data.

Related file types