Windows NT time is specified as the number of 100 nanosecond intervals since January 1, 1601. UNIX time is specified as the number of seconds since January 1, 1970. There are 134,774 days (or 11,644,473,600 seconds) between these dates.
How to convert Windows NT Time to UNIX Time:
Divide by 10,000,000 and subtract 11,644,473,600.
How to convert UNIX Time to Windows NT Time:
Add 11,644,473,600 and multiply by 10,000,000.
Yeah, that wasn’t funny at all. Yay for lack of documentation!