I think you're overthinking this.

If a user is in Florida and their settings are correct for local time zone
the data is stored as UTC, compensated by the local time zone offset. If the
user flies to California and they want UTC times to be correct for that
local time zone they can set the Outlook time zone, add an alternate time
zone and/or change the Windows time zone. Then everything is correct for
local time again.

This is the exact same thing for every single date field in every Outlook
item. If when the date values are entered the time zones are correct the
data is correct in UTC and that's all you can ever expect. If the user
changes time zones and doesn't update their settings every single one of
their date fields will be off by some offset to local time.

--
Ken Slovak
[MVP - Outlook]
http://www.slovaktech.com
Author: Professional Programming Outlook 2007.
Reminder Manager, Extended Reminders, Attachment Options.
http://www.slovaktech.com/products.htm


"Mark B" wrote in message
...
Yes I tend to agree.

The only downside to creating an additional user-defined field called
MileStone1LocalTime is if the add-on is stored on somebody'slaptop and
they tend to be a jet-setter (e.g. travelling salesperson) and frequently
enter different timezones. Then the hard-coded local time is no longer
relevent.

I suppose the way around this is to store the UTC offset in settings and
check that it is the same on Addin startup. If it's not I'd probably need
a messagebox saying "time-zone adjustments need to be made -- this can
take a few minutes." and then proceed to loop through all emails in all
folders, updating the user-defined field value and saving each one. This
would need to be on the main thread since if I tried to do it in the
background it would appear to hang.