SQL Server 2019 crashed: how to detect the reason?

Question

My SQL Server crashed these days with MessageBox on servers screen:

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VS Just-In_time debugger:

"An unhandled Microsoft .Net Framework exception occurred in sqlservr.exe 12156"

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I could not find any explanations about this problem. Also, restart the service did not help.
I have installed all updates for Windows Server, all CU for SQL Server 2019 , restarted the Windows Server and again the same error

What can be the reason? what should I check?

Answer 1

Hi @WinnieTP ,
How about focus on the error information that

VS Just-In_time debugger:

VS is also an important part of SQL
Try deleting the debug file in the registery. The location is :【HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AeDebug\Debugger 】

Another location:【HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft.NETFramework\DbgManagedDebugger 】

The same as :HKEY_LOCAL_MACHINE/SOFTWARE/Wow6432Node/Microsoft/Windows NT/CurrentVersion/AeDebug/Debugger

HKEY_LOCAL_MACHINE/SOFTWARE/Wow6432Node/Microsoft/.NETFramework/DbgManagedDebugger

At last step reinstall the VS and restart your computer.

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Answer 2

Does really the SQL Server database engine or SSMS = Management tool crash?
If database engine crashs, there should be dump file in log folder.

Answer 3

Yes, it is SQL Server 2019. The SSMS is not a problem, I have it on other machine etc.
But the server with databases is crashed.
Btw, I have 3 SQLCLR assemblies in database on this SQL Server.

Answer 4

Hi @WinnieTP ，
Is it possible that the antivirus software delete your net framework by mistake? How about trying reinstalling the net framework from this website: https://dotnet.microsoft.com/en-us/download/dotnet-framework. Install and restart your computer. If it is possible you may shut down your antivirus software for a while.

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Answer 5

Often when SQL Server crashes, it is due to a bug in the product. However, before you open a support case, there are a few things you should check, and to cut it short, you have already mention one of these: unsafe CLR assemblies. Well, you did not say that they are unsafe, but I assume they are. And a incorrectly written unsafe assembly can indeed bring SQL Server on its knees.