I\'m writing a CSV file. I need to write timestamps that are accurate at least to the second, and preferably to the millisecond. What\'s the best format for timestamps in
Go to the language settings in the Control Panel, then Format Options, select a locale and see the actual date format for the chosen locale used by Windows by default. Yes, that timestamp format is locale-sensitive. Excel uses those formats when parsing CSV.
Even further, if the locale uses characters beyond ASCII, you'll have to emit CSV in the corresponding pre-Unicode Windows "ANSI" codepage, e.g. CP1251. Excel won't accept UTF-8.