A worker process serving the application pool terminated unexpectedly.
A process serving application pool ''%1'' terminated unexpectedly. The process id was ''%2''. The process exit code was ''0x%3''.
If this happens frequently enough, it could trigger Rapid Fail Protection. Consider what applications are running in that application pool and try to isolate the application causing the problems. Other tools, like ADPlus, can be used to capture the crash for debugging purposes.