I am getting these unexpected shutdown errors as well now (Restarted after unexpected shutdown (1500/40)). There is an error in the Application Event Viewer that corresponds to the time BI crashed.
Lately, I have been getting this about once a day.
Faulting application name:
BlueIris.exe, version: 5.2.8.3, time stamp: 0x5ec92f68
Faulting module name: VCRUNTIME140.dll, version: 14.23.27820.0, time stamp: 0x5d0b2812
Exception code: 0xc0000005
Fault offset: 0x00000000000012de
Faulting process id: 0x2fbc
Faulting application start time: 0x01d636cac8bb5471
Faulting application path: C:\Program Files\Blue Iris 5\BlueIris.exe
Faulting module path: C:\WINDOWS\SYSTEM32\VCRUNTIME140.dll
Report Id: 632eb626-1aac-4ef7-9b37-90f1aba50f51
Faulting package full name:
Faulting package-relative application ID: