How to Disable Retention Policy from Applying on Calendar and Tasks in Exchange 2010 – (Calendar and Tasks Disappeared)

Till Exchange 2010 Sp2 Ru3 – MRM never gets applied on Calendar and Tasks


But in the release of Exchange 2010 Rollup 4

This has been included.

Past –

Retention policies do not work for the Calendar and Tasks folders in an Exchange Server 2010 SP1 environment

Present – Exchange 2010 Sp2 Ru4 or above

what you should know is

Retention policies do work for the Calendar and Tasks folders in an Exchange Server 2010 SP2 Ru4 or above environment


So if you have a policy which is applied for all Folders in the mailbox in the past – Once you upgrade to Exchange 2010 Sp2 ru4 or above

Retention Policy will apply on “Calendar and Tasks” where the old items are going to expire and retention action will take place as per the policy


So all of a sudden your old calendars and tasks got disappeared or got deleted . This will be the most possible reason.

you can find the items as per the retention action has been taken place.


If you feel “Calendar and Tasks” should not get deleted , If you feel this will not suit your environment.


Before applying the Exchange 2010 sp2 Rollup 4  or upgrading above Exchange 2010 Sp2 Rollup 4

There is a registry tweak available to disable them from the server end. Where this design change won’t get effect in your environment.


Open Regedit on you all your mailbox servers

Start- Run – Regedit


Browse to the below location



Create a New “DWORD (32-bit) Value”


Enter the Value – ELCAssistantCalendarTaskRetentionEnabled



To disable this Design Change – (MRM won’t apply on Calendar and Tasks)

Type Decimal Value – 0


Later, To enable this Design Change – (MRM will apply on Calendar and Tasks)

Type Decimal Value – 1



Hope this article will clear some confusions !!

About Satheshwaran Manoharan

Satheshwaran Manoharan is an Microsoft Office Server and Services MVP , Publisher of Specialized in Office365 / Microsoft Exchange / Virtualization , Sathesh is an Messaging Expert supporting/Designing/Deploying many medium size businesses to large enterprises when it comes to Corporate messaging and Virtualization Infrastructure

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One comment

  1. What about if I need Tasks to be excluded but still want the calendar items to be archived according to Retention Policy though ?

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