qgis - What is a crash dumped / crash minidump?

There are lots of posts to do with QGIS crashing; they tend to deal with specific instances and conditions.

But this has led me to want to know what is a crash minidump?

What is happening, is there a simple answer?

The background leading up to this is that I have a user that has a crash minidump every time that they close QGIS (2.14.9), even though many others are using the same version, on exactly the same machines, of the same age and make without issue.

Then myself, using QGIS 2.16 , I was testing out an answer from Merging attribute and geometric features in QGIS? it gave me a crash minidump each time I tried dissolve vectors. So I decided to uninstall 2.16, and install 2.18

But before I did this I looked for information on crash minidump and yes, the main accepted advice, which works, is to Delete C:\users\name.qgis2 before re-installing

But what is a crash minidump, what’s happening?

Edit added

The user mentioned above, after a of week of no crash mini dump's, is again reporting that the issue is back. Again every time they close QGIS?

What actually causes QGIS to crash? Could it be a hardware issue possibly?

Answer

Windows automatically generates a minidump whenever a program throws an unhandled exception: https://msdn.microsoft.com/ru-ru/library/windows/desktop/ee416349%28v=vs.85%29.aspx

You can open these minidumps with a program like WinDbg to get an idea what caused the exception:

We tried to find the reason for the exceptions when QGIS crashed quite often. Even with our paid QGIS-Support we could not find the reasons for the QGIS-crashes and were told that the minidumps are not necessarily helpful.

A better way for us was to use the QGIS-rel-dev version which writes debug-outputs and listen to these debug-outputs with a program like DebugView (https://technet.microsoft.com/en-us/sysinternals/debugview.aspx ):

If you install qgis-rel-dev with the OsGeo4W-Installer you can start this QGIS-version with the qgis-rel-devXXX.bat file:

In the about-dialog of QGIS you can see if your QGIS-version writes debug outputs:

If you start DebugView and work with QGIS until it crashes you should see what tools / functions were involved when the crash happened: