What Is a .DMP File?
You found a big .dmp file (maybe memory.dmp) eating gigabytes of disk. It is a crash dump Windows saved after a failure. Here is what it holds and how to clear it safely.
What a DMP file is
A .dmp file is a memory dump — a snapshot of what was in memory at the moment a program crashed or Windows hit a blue screen. Developers and the Windows debugger read it to find the cause. The system one, C:\Windows\memory.dmp, can be huge; smaller minidump files (a few hundred KB) live in C:\Windows\Minidump.
Where they come from
A kernel crash (BSOD) writes a full or kernel dump. Individual app crashes drop .dmp files too, often in your %LocalAppData%\CrashDumps folder. One or two is normal; a pile of them means something is crashing repeatedly.
Is it safe to delete?
Yes, unless you plan to have someone diagnose the crash. Deleting a .dmp only removes the diagnostic snapshot — it does not affect Windows or your files. Use Disk Cleanup (tick System error memory dump files) rather than deleting memory.dmp by hand, since it may be locked.
How to read one
If you want the cause, open the dump with the free WinDbg tool or a viewer like BlueScreenView, which lists the driver that likely triggered the crash.
FAQ
Can I delete memory.dmp?
Yes. It is only a crash snapshot. Use Disk Cleanup's 'System error memory dump files' option so a locked file is handled cleanly.
Why do I keep getting .dmp files?
Something is crashing repeatedly — a faulty driver or app. Read the dump with BlueScreenView to find the culprit.
How big should a .dmp be?
Minidumps are a few hundred KB; a full memory.dmp can be as large as your RAM.