Windows Memory Diagnostic: Run It and Read the Results

Random freezes or crashes can make a memory problem worth checking, but they do not prove that the RAM is faulty. Windows includes a built-in memory test that can look for errors during a restart. Its result is a useful clue; a clean run is not a guarantee that every crash has been explained.

Windows Memory Diagnostic is built into Windows. Microsoft’s memory troubleshooting instructions describe how to start it with mdsched and run the restart-based test. The steps below cover this diagnostic, not every possible cause of a crash.

Before you run the test

Save your work and close open programmes. The check restarts the PC, so anything unsaved could be lost. You do not need to download a separate test app.

Windows Memory Diagnostic checks for possible memory errors. It is not a way to measure whether your PC has enough RAM for a workload, and it does not identify the cause of every slowdown or crash.

Run Windows Memory Diagnostic

1. Open Start and search for Windows Memory Diagnostic. You can also press Windows key + R, enter mdsched, and select OK.
2. Select Restart now and check for problems (recommended) when you can leave the PC alone.
3. Let the computer restart and finish the test. Windows will start again when the check is complete.
4. Sign in and look for the Windows Memory Diagnostic result notification.

Save open work before choosing the restart option. A December 2024 answer by a Microsoft Community Support Specialist also documents that the check runs after restart and that a result notification can appear after Windows returns. Read the documented restart and result flow.

Find the result if you missed the notification

Open Event Viewer from the Start menu. Expand Windows Logs, select System, then use Filter Current Log and choose MemoryDiagnostics-Results as the event source. Look for the entry created at the time of your test.

The result event is different from the entry saying that a test was scheduled. The December 2024 Microsoft Community Support answer documents the System log location and source name; a Microsoft Support Community answer from 2020 records the same result source.

Decide what to do with the result

If Windows says it found no memory errors, the careful reading is that this run did not report one. It does not certify the memory for every future workload or rule out another cause for a crash. If the problem continues, note the stop code, time and what the PC was doing. Then check for recent hardware or firmware changes and use the diagnostic guidance for your exact PC or motherboard.

If the test reports hardware errors, save the result and contact the PC maker or system builder for next steps. The message is a reason to investigate the memory subsystem; it is not, by itself, a verdict about which module or slot to replace. Avoid opening a laptop or changing firmware settings based on a single message if you are not comfortable following the maker's instructions.

Did the crashes begin after you enabled a memory profile? Our guide to checking XMP or EXPO settings and system stability explains why a profile can make a system unstable and how to return to the previous setting using the motherboard maker's instructions.

Treat Windows Memory Diagnostic as one step in a diagnosis: a reported error deserves follow-up, while a clean result is only one piece of evidence about a problem that keeps happening.