sorry Gail...

It hangs on a select into, but the step itself truncates a table, then selects data and put it back into the table.

Run the statement separately, it runs fine.

It's not waiting for a file - the data is all present and correct (hence it will run as normal as soon as the service is restarted)

There are no wait types - as I say, it doesn't appear to be processing at all. It starts, then literally does nothing. There is nothing unusual under sp_who2, activitity monitor, Adam Machanic's sp_whoisactive etc

When I run it against a script using sys.dm_os_tasks joined withdm_os_waiting_tasks, it will show the state as running, but there are no wait types, no blocking sessions, no resource_description etc

I'm afraid I've lost the crystal ball.