Outlook True Archive works with all 32-bit and 64-bit versions of Windows released since 2001, including Windows XP, Vista, 7 and 8.
Outlook works with 32-bit version of Office only. It does not work with 64-bit versions of Office.
If you are in any doubt, download the trial version and test for yourself.
If you are using Office 64-bit and need to archive mails and calendar events from your Outlook, you may be able to do so if you have access to another PC with Office 32-bit installed. As the PST file format is the same, you can transfer the PST to the PC with Office 32-bit installed, run Outlook True Archive on that PC and then transfer the PST (and archive file(s)) back to the original PC. Alternatively, the PST can be left on a network drive where both PCs have access. (NB: Only one PC can open a PST file at a time.)
Outlook True Archive uses the Microsoft API calls to open the PST file(s) which include your mails and calendar items to be archived. The software tools developed to do this are available in 32-bit versions but not yet in 64-bit versions. Naturally, we would wish to offer a 64-bit version as soon as possible and will do so, once a tested set of the development tools is available.
The availability of a version to support 64-bit versions Office will be announced on these pages once it is released.