About once a week, at completely random times, my remote probe service will crash and show everything down, which in turn sends out an e-mail and SMS for all 172 of my sensors being down. Once I go in and restart the remote probe service, everything shows as back up and I get all the pages that things are coming back up.
This has been happening for the last couple of versions I have ran of PRTG and it has not gotten any better when I upgrade; I am currently running 220.127.116.11. My probe computer monitors mostly pint, snmp, and wmi. The probe service is running on a P4 2.8 machine with 2GB of memory.