Recover from future times in the snapshot

Stop PI Snapshot Subsystem (the pisnapss process) on a running Data Archive server.

Restart PI Snapshot Subsystem from a command prompt and pass the -f argument:

pisnapss -f

This must be done interactively, not as a Windows service. On startup, PI Snapshot Subsystem looks for all snapshots more than 20 minutes in the future. These future snapshots are overwritten with a NULL value. PI Snapshot Subsystem reports the number of future events detected to the message log. If no future snapshots were detected, no fix messages are written to the message log. New incoming data immediately overwrites the NULL snapshot, even if the incoming value is out of order.

PI Snapshot Subsystem continues to run normally after the fix.

Press Ctrl+C in the interactive pisnapss process and restart it as a service.

Note: Snapshots fixed by this procedure remain set to NULL until a new snapshot event arrives. A NULL snapshot value is replaced by any new event that is received for a point, even if the event is an out-of-order event.