Retention policy on Calendar and Task folders. Confused ?

Beginning with Exchange 2010 SP2 RU4, administrators can create tags use with the Calendar and Tasks default folders. The supported retention actions are: DeleteAndAllowRecovery, PermanentlyDelete, MarkAsPastRetentionLimit.

Calendar and Tasks Retention Tag Support in Exchange 2010 SP2 RU4

https://blogs.technet.com/b/exchange/archive/2012/08/14/calendar-and-tasks-retention-tag-support-in-exchange-2010-sp2-ru4.aspx

Below are common question raised regarding processing of Calendar and Tasks folder.

Question : Can I only configure only the Calendar folder to be processed and not Tasks folder ?

Answer : No. Using the registry key mentioned in the blog,we can either disable or enable processing of both Calendar and Tasks folders.

Incase you need only Calendar to be processed as per the retention tag and disable processing of Tasks folder (or vise versa),then the registry key mentioned in the blog should be enabled and create a disabled Personal tag with Archive action and apply this disabled Personal tag on Tasks folder using available EWS script.

Important to note that by creating a disabled RPT for Tasks , when you have a DPT with move to archive action is not going prevent Tasks folder from being processed,in this case DPT is going to process the Tasks folder and move the content from Tasks folder to archive,even thou you have a disabled RPT for Task in place.The Tasks items will be moved to archive and the disabled RPT for Tasks will be applied to Tasks folder in Archive.

Question :As mentioned in the blog,we can use RPT on Calendar or Tasks folder inorder to have a different retention period,but DPT with move to archive is overwriting the RPT for Calendar or Tasks folder ?

Answer : Usually when support for Calendar and Tasks folder is enabled and you have a DPT with move to archive action in the policy.The DPT will move items from Calendar and Tasks folder to archive  .To avoid this we create a RPT for Calendar or Tasks folder with higher retention age or disable this tag.But if the Retention age of DPT is lower than RPT for Calendar and Tasks folder,the DPT is still going to process Calendar and Tasks folder and move items to archive.This is default behavior.

Refer :

DPT with move to archive action takes precedence over RPT.

https://blogs.technet.com/b/vikass_blog/archive/2013/07/04/dpt-with-move-to-archive-action-takes-precedence-over-rpt.aspx

The blog does mentions to create a RPT for Calendar and Tasks folder to have a different retention age,this is only applicable if you have a DPT with action other than move to archive in the policy and you want to avoid DPT from processing Calendar and Tasks folder.

Calendar items are tagged ,Need to untag them !

Consider you have already applied a policy to mailboxes,which has a default policy tag .Post applying Exchange 2010 SP2 RU4 or later you would find that the calendar items are tagged with expiry date. This is because after applying Exchange 2010 SP2 RU4 or later,the support for Calendar and Tasks items is enabled by default.

If you don't want Calendar and Tasks not to be processed,you can add the below registry key prior installing Exchange 2010 SP2 RU4 or later.
•Path: HKLM\SYSTEM\CurrentControlSet\Services\MSExchangeMailboxAssistants\Parameters
•Name: ELCAssistantCalendarTaskRetentionEnabled
•Type: DWORD
•Value: 0 = Do not process Calendar and Task folders
•Value: 1 = Process (default with RU4)

It is important to plan whether you need Calendar and Tasks folder to be processed prior installing Exchange 2010 SP2 RU4 or later.

Incase you have missed adding the above registry key prior to upgrading to Exchange 2010 SP2 RU4 or later,you would see that the Calendar items are processed or tagged with an expiry date.This happens if your policy has a Default policy tag.

At this point,if you modify the registry and set the  ELCAssistantCalendarTaskRetentionEnabled to 0.The Calendar and Tasks folder wont be processed,but the calendar items which were tagged with an expiry date, would remain tagged,thou assistant will not process these Calendar items in the Calendar folder.

Inorder to remove the tags from calendar items.we can follow the below steps;

1. Place the mailboxes on Retention hold.

2. Enable processing of Calendar and task folder by either deleting the registry entry or by setting the ELCAssistantCalendarTaskRetentionEnabled  to 1.If this registry entry doesn't exist it means that processing of Calendar and Tasks folder is enabled,which is by default.

3. Remove the tag affecting the calendar items from the policy,which is usually a DPT.

4. Give enough time for AD replication for changes to take effect and assistant to process the mailboxes.

5. Confirm that the calendar item are now untagged.

6. Modify the registry key and set the ELCAssistantCalendarTaskRetentionEnabled to 0.

7, Add the tag back to the policy.

Note that the registry modification once done takes some time to take effect.

Note : This registry is specific to server,therefore inorder to disable Calendar and Tasks folder from processing,we need modify the registry on all Exchange 2010 & Exchange 2013 servers.

Hope it helps!

-Vikas