Product and version: FileMaker Server 184.108.40.206
OS and version: Windows Server 2012R2 Version 6.3 (Build 9600)
Browser and version (for WebDirect only): Client browsers vary. Typically iPhone Safari or Android Chrome.
Hardware: Virtual machine. AWS Windows AMI running on an m5.large instance.
Description: The FileMaker Server service (fmshelper.exe) faults on ucrtbase.DLL seemingly at random, causing all related related processes (fmserver.exe, fmscwpc.exe, fmsase.exe, etc.) to quit. Windows Error Reporting did generate dump files and other logs, which I can provide to FileMaker if requested. This server hosts only one file that is accessed primarily via WebDirect by fewer than ten users at a time.
How to replicate: It's not clear how to replicate this issue.
Workaround (if any): There isn't a clear workaround. Resolving the issue requires logging in to the Windows OS and starting the FileMaker Server service manually. On at least one occasion, after starting the FileMaker Server service and confirming that the Launch Center page was reachable, the WPE Master Machine showed as unavailable and attempting to access files via WebDirect showed an error page. The recommendations here and here did not bring the Master Machine online (however fmsadmin restart jwpc has resolved similar Master Machine issues on other 17 deployments). A full reboot of the instance was required to bring everything online.