.MSG File Format – All PidTag properties

The 577 numbered properties of the form PidTag… in section 2 of [MS-OXPROPS] (the learn.microsoft.com PDF of the specification, read 2026-11-13). A tag is the 16-bit property ID plus a 16-bit type; in a property stream the tag is written as ID then type (0037001F is PidTagSubject), see the property stream. The named properties are on the PidLid and PidName pages; the commonly used tags with their meanings are on the storages and properties page. For each property the specification also has a description, defining and consuming references and the old PR_ names; this page gives identity, type and area.

Columns. ID is the property ID in hexadecimal (4 digits); Type drops the Ptyp prefix, and where the specification names two types for one ID (for example 0x3701 as Binary or Object) there is a row for each. The values String (001F) and String8 (001E) are the Unicode and 8-bit string types. Area is the specification's own grouping; the trailing word "Properties" is left out. Several different properties share an ID where their areas differ (for example 0x8005 below); the object they apply to decides which is meant.