ERROR_DS_RESERVED_MAPI_ID 0x800721B7

Error code 8631 · HRESULT 0x800721B7

WINDOWS

Schema update failed: The MAPI identifier is reserved.

Windows troubleshooting diagram: Device Manager warning and a system file scan
Windows errors: check drivers, system files and Event Viewer, in that order.

What it means

ERROR_DS_RESERVED_MAPI_ID is a Windows error code (system error 8631, returned as HRESULT 0x800721B7) reported by Windows. Its official message is: “Schema update failed: The MAPI identifier is reserved.”

How to fix ERROR_DS_RESERVED_MAPI_ID

  1. Reboot once — many one-off system codes disappear with a clean restart
  2. Repair system files: 'sfc /scannow' then 'DISM /Online /Cleanup-Image /RestoreHealth'
  3. Find the source in Event Viewer → System: filter for this exact code and open its provider link

Related errors

ERROR_DS_RESERVED_LINK_IDERROR_DS_DRA_SECRETS_DENIEDERROR_DS_MAPI_ID_NOT_AVAILABLEERROR_DS_DRA_CORRUPT_UTD_VECTORERROR_DS_DRA_MISSING_KRBTGT_SECRETERROR_DS_HIERARCHY_TABLE_TOO_DEEPERROR_DS_DOMAIN_NAME_EXISTS_IN_FOREST

Source: Microsoft WinError.h

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