Microsoft Outlook stores these items in a personal-storage-table (.pst) or off-line-storage-table (.ost) files that are located on the local computer.
[6] The password to access the table is stored without the first and last XOR CRC-32 integer representation of itself in the .pst file.
Microsoft (MS) offers three values for the encryption setting: none, compressible, and high.
MVCOM is a commercially licensed COM Component that provides access to .pst files without MAPI.
[10] Outlook 2002 and earlier use ANSI (extended ASCII with a codepage) encoding for their .pst and .ost files.
[11] From Outlook 2003 and onward, the new standard format for .pst and .ost files is Unicode (UTF-16 little-endian), with 64-bit pointers instead of 32-bit to allow larger than 2 GiB sizes.
[12][11][13] A file that is created in the personal-folders format in Outlook 2003 or later is not compatible and cannot be opened by earlier versions.
While superficially similar to Outlook, it was an entirely different application, and used a unique database format which cannot be imported or exported, though user data can be imported and exported to and from another unique format called .rge (a bundle consisting of many individual files plus metadata).
Entourage's replacement, Outlook for Office 2011 for Intel Macs, was able to import Outlook .pst files from Windows;[14] however, data will be stored as many individual files, rather than in a single database such as .pst or the Entourage database.