PidTagStoreSupportMask Canonical Property

Applies to: Outlook 2013 | Outlook 2016

Contains a bitmask of flags that client applications query to determine the characteristics of a message store.

Property Value
Associated properties:
Data type:


This property discloses the capabilities of a message store to client applications that are planning to send it a message. The flags can support decisions by a client or another store, such as whether to send PR_BODY (PidTagBody) or only PR_RTF_COMPRESSED (PidTagRtfCompressed). A client should never set PR_STORE_SUPPORT_MASK; an attempt to set this flag returns MAPI_E_COMPUTED.

One or more of the following flags can be set for the PR_STORE_SUPPORT_MASK bitmask:


(131072, 0x00020000) The message store supports properties that contain ANSI (8-bit) characters.


(32, 0x00000020) The message store supports attachments (OLE or non-OLE) to messages.


(1024, 0x00000400) The message store supports categorized views of tables.


(16, 0x00000010) The message store supports creation of new messages.


(1, 0x00000001) Entry identifiers for the objects in the message store are unique, that is, never reused during the life of the store.


(65536, 0x00010000) The message store supports HTML messages, stored in the PR_BODY_HTML (PidTagBodyHtml) property. If your development environment uses a MAPIDEFS.H file that does not include STORE_HTML_OK, use the value 0x00010000 instead.


(2097152, 0x00200000) In a wrapped PST store, indicates that when a new message arrives at the store, the store performs rules and spam filter processing on the message separately. The store calls IMAPISupport::Notify, setting fnevNewMail in the NOTIFICATION structure that is passed as a parameter, and then passes the details of the new message to the listening client. Subsequently, when the listening client receives the notification, it does not process rules on the message.


(524288, 0x00080000) This flag is reserved and should not be used.


(8, 0x00000008) The message store supports modification of its existing messages.


(512, 0x00000200) The message store supports multivalued properties, guarantees the stability of value order in a multivalued property throughout a save operation, and supports instantiation of multivalued properties in tables.


(256, 0x00000100) The message store supports notifications.


(64, 0x00000040) The message store supports OLE attachments. The OLE data can be accessed through an IStorage interface, such as that available through the PR_ATTACH_DATA_OBJ (PidTagAttachDataObject) property.


(16384, 0x00004000) The folders in this store are public (multi-user), not private (possibly multi-instance but not multi-user).


(8388608, 0x00800000) The MAPI Protocol Handler will not crawl the store, and the store is responsible for pushing any changes through notifications to the indexer to have messages indexed.


(2, 0x00000002) All interfaces for the message store have a read-only access level.


(4096, 0x00001000) The message store supports restrictions.


(2048, 0x00000800) The message store supports Rich Text Format (RTF) messages, usually compressed, and the store itself keeps PR_BODY and PR_RTF_COMPRESSED synchronized.


(268435456, 0x10000000) Indicates that rules should be stored in this PST store even if it is not the default store. When STORE_RULES_OK is used in conjunction with NON_EMS_XP_SAVE, rules are able to run on non-default PST wrapped stores.


(4, 0x00000004) The message store supports search-results folders.


(8192, 0x00002000) The message store supports sorting views of tables.


(128, 0x00000080) The message store supports marking a message for submission.


(32768, 0x00008000) The message store supports storage of RTF messages in uncompressed form. An uncompressed RTF stream is identified by the value dwMagicUncompressedRTF in the stream header. The dwMagicUncompressedRTF value is defined in the RTFLIB.H file.


(262144, 0x00040000) Indicates that the message store supports Unicode storage. A client can look for the presence of the flag to decide whether to request or to save Unicode information to the store.

An RTF version of a message can always be stored, even if the message store is non-RTF-aware. If the STORE_RTF_OK bit is not set for a particular store, a client maintaining RTF versions must itself call the RTFSync function to keep the PR_BODY and PR_RTF_COMPRESSED versions synchronized for text content. RTF is always stored in PR_RTF_COMPRESSED, whether it is actually compressed or not.

Protocol specifications


Provides references to related Exchange Server protocol specifications.


Describes the format of messages used to send information related to sharing folders on the client.

Header files


Provides data type definitions.


Contains definitions of properties listed as alternate names.

See also

MAPI Properties

MAPI Canonical Properties

Mapping Canonical Property Names to MAPI Names

Mapping MAPI Names to Canonical Property Names