After years of flawless running I've just started getting static snapshot error 1259 each time I try to back up my main snapshot. The text of the error is "unable to create static copy of active snapshot". I've done a fresh reinstall of FD-ISR, choosing the option to delete previous snapshots in the process but a copy operation just stops with this error after 2 seconds. I suspect this has something to do with the VSS service, which appears to be running OK, though. Any suggestions I could try?