Where crash dumps come from and how much they eat
After a blue screen (BSOD), Windows writes C:\Windows\MEMORY.DMP — a snapshot of kernel memory whose size depends on the dump type configured in Startup and Recovery. A small memory dump is 256 KB per crash, while an automatic or kernel dump typically runs several hundred megabytes up to a few GB. Alongside it, every crash also leaves a compact .dmp file in the C:\Windows\Minidump folder, so a PC that blue-screens weekly collects dozens of them within a few months.
User-mode applications crash too, and their dumps live in a separate place: %LOCALAPPDATA%\CrashDumps, where each failing app can deposit .dmp files well past 100 MB. A third corner is C:\Windows\LiveKernelReports, which collects dumps from GPU hangs and watchdog events that never actually blue-screened. None of these files are needed for Windows to run — they exist purely so a crash can be analyzed afterwards with tools like WinDbg.
- C:\Windows\MEMORY.DMP — kernel dump from the last blue screen, 256 KB up to several GB
- C:\Windows\Minidump\*.dmp — one compact dump per BSOD, roughly 256 KB to 2 MB each
- C:\Windows\LiveKernelReports — dumps from GPU hangs and watchdog events without a blue screen
- %LOCALAPPDATA%\CrashDumps — crash dumps of individual apps, often over 100 MB
- %PROGRAMDATA%\Microsoft\Windows\WER — error reports that often carry attached dumps
Deleting the dumps safely
The clean built-in route is Disk Cleanup: run cleanmgr as administrator, click “Clean up system files”, and tick “System error memory dump files” plus “System error minidump files”. The same items appear in Settings → System → Storage → Temporary files. This removes exactly the dump categories without touching anything personal, and shows the space you get back before confirming.
Manual deletion works too and reaches what Disk Cleanup misses. From an elevated command prompt, del /f /q C:\Windows\MEMORY.DMP removes the kernel dump, del /f /q C:\Windows\Minidump\*.dmp empties the minidump folder, and rd /s /q "%LOCALAPPDATA%\CrashDumps" wipes the app-dump folder. If a file answers with “access denied”, a fresh crash has just rewritten it — delete it right after a reboot. While blue screens are still happening, keep the newest Minidump files: they are the raw material for finding the failing driver.
Stopping Windows from filling the disk again
Dump settings live in System Properties → Advanced → Startup and Recovery → Settings. The dropdown “Write debugging information” decides what a crash leaves behind: “Automatic memory dump” is the Windows default, while “Small memory dump (256 KB)” caps the damage at a few hundred kilobytes per blue screen. If you never analyze crashes yourself, switching to small dumps — or disabling the dump entirely — saves the most space and costs nothing you will miss.
Keep in mind that dumps are a symptom, not the disease. A folder that keeps refilling means something is crashing, and the fix belongs there — usually an unstable GPU driver, faulty RAM or an overly aggressive antivirus filter. Update the usual suspects, run a memory test if crashes repeat, and the dump folders stay empty on their own.
Questions and Answers
Is it safe to delete MEMORY.DMP?
Yes. MEMORY.DMP is only a crash snapshot kept for diagnosis; Windows runs fine without it. If the crash that created it is already resolved, delete it and claim the space.
Why can't I delete a .dmp file — access denied?
The file is held by the system or by an app that just crashed again. Delete it right after a reboot; the error itself is harmless.
Where does Windows store minidump files?
In C:\Windows\Minidump — one .dmp file per blue screen. The kernel dump of the latest crash sits separately in C:\Windows\MEMORY.DMP, and app crash dumps land in %LOCALAPPDATA%\CrashDumps.
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