Exchange Unicode Mode - Ignore OST Format

This policy setting allows you to specify whether existing OST format determines the mailbox mode.

If you enable this policy setting, you may choose one of these options:

* OST Format determines mode: the format of the user's OST file will be used to determine whether to run in Unicode or ANSI mode.
* Create new OST if format doesn't match mode: create a new OST file if needed.
* Prompt to create new OST if format doesn't match mode

If you disable or do not configure this policy setting, you will not be able to specify whether existing OST format determines the mailbox mode.

This policy is ignored if PreferANSI is not set and the OST is enabled but either does not exist or is a Unicode OST, because it would be impossible for the user to create an ANSI OST.

Supported on: At least Windows 7

Choose whether existing OST format determines mailbox mode


  1. OST Format determines mode
    Registry HiveHKEY_CURRENT_USER
    Registry Pathsoftware\policies\microsoft\office\15.0\outlook\emsp
    Value Nameignoreostformat
    Value TypeREG_DWORD
    Value0
  2. Create new OST if format doesn't match mode
    Registry HiveHKEY_CURRENT_USER
    Registry Pathsoftware\policies\microsoft\office\15.0\outlook\emsp
    Value Nameignoreostformat
    Value TypeREG_DWORD
    Value1
  3. Prompt to create new OST if format doesn't match mode
    Registry HiveHKEY_CURRENT_USER
    Registry Pathsoftware\policies\microsoft\office\15.0\outlook\emsp
    Value Nameignoreostformat
    Value TypeREG_DWORD
    Value2


outlk15.admx

Administrative Templates (Computers)

Administrative Templates (Users)