All of the sudden since sometime last week, optimizations which take several hours started crashing.

QUOTE:
Application: WealthLabDev.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an internal error in the .NET Runtime at IP 00007FFFDB4F5814 (00007FFFDB450000) with exit code 80131506.

QUOTE:
Faulting application name: WealthLabDev.exe, version: 1.0.0.0, time stamp: 0x5e32bb73
Faulting module name: clr.dll, version: 4.8.4220.0, time stamp: 0x5f03ab02
Exception code: 0xc0000005
Fault offset: 0x00000000000a5814
Faulting process id: 0x4164
Faulting application start time: 0x01d69fd00729507e
Faulting application path: C:\Program Files\MS123\Wealth-Lab Developer 6\WealthLabDev.exe
Faulting module path: C:\Windows\Microsoft.NET\Framework64\v4.0.30319\clr.dll
Report Id: 88941b8c-e03c-4b11-8a70-b29bdcb4604e
Faulting package full name:
Faulting package-relative application ID

I have never had any problem like this in the past.
Has anyone experienced the same problem recently?

I'm suspecting if it is something to do with this latest Windows Update.
KB4576484 Cumulative Update for .NET Framework 3.5 and 4.8 for Windows 10 Version 1903

I just uninstalled it to see if the problem persists.

According to StackOverflow, exit code 80131506 may be caused by a spectre of various reasons. Too generic. Let's see if uninstall helps.

0xc0000005 is an access violation and it occured in clr.dll which I believe .NET Runtime to bail out thus terminated WealthLabDev.exe.

Since uninstalled the .NET Framework Update, so far looks good.
All the optimization has completed without crashing WLD.
If your WLD started crashing, you may try uninstalling KB4576484.

Thanks, just added it to the Wiki.