On 9/7/2012 7:09 AM, jrl wrote:

Hmm,

At one time, the registry hives contained timezone information. An immediate search for the word TimeZone in the registry produces (Windows 7) yields: {BED7F4EA-1A96-11D2-8F08-00A0C9A6186D} Which points to a 64 bit Framework item... C:\Windows\Microsoft.NET\Framework64\v4.0.30319

Is it possible the Windows time zone data has been moved out to the GAC - is it now in both places?

No, you left off the space. HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones.