Deleted and Junk mail folder won't delete after X days

[David_S876]

We recently migrated over to Office 365 (been a few months) and I noticed that my deleted folder and junk mail folder don't automatically delete after 30 days, like it use to.

I have been reading over Retention policies option in Microsoft Purview admin but I'm not quite sure how to apply it to the Deleted and Junk mail folder automatically for all users.

Would love some guidance on getting this done.

[#2 · Accepted solution]

Retention policies is the way to go, however you need to use the "old style" Exchange retention policies, as only they can target specific folders. Go to the Compliance portal > Data lifecycle management > Exchange. Under MRM retention tags, make sure you have a "Deleted items" tag with the corresponding action/duration. Then under the MRM retention policies tab, make sure the Delete items tag is added to any policies currently assigned to your users. Rinse and repeat for the Junk email tag.

[#3]

@Vasil MichevHey Vasil, thanks much for the feedback.

I see I do have some default retention tags already set, and I see Delete folder and Junk Mail folder included.

There is also a Default MRM Policy under the MRM Retention Policies tab, but this default policy doesn't seem to be applied to anyone's account on the server, including mine.

Is there a way to turn this Default policy on for all mailboxes?

[#4]

Do you see any other policies listed? In Exchange Online, mailboxes do get a policy by default, but you might be using a custom-created one. You can check the mailbox properties via the EAC or PowerShell:

Get-Mailbox | ft Name,RetentionPolicy

[#5]

@Vasil MichevNo other policies are listed other than Default MRM Policy.

Keep in mind, we had migrated from Exchange 2010 to Exchange Online. So not sure if the default policies were applied to the migrated accounts during migration.

Here is a snippet of the output of the Powershell command. All the users don't have the Default MRM Policy applied. Only these names with random numbers.

PS> Get-Mailbox | ft Name,RetentionPolicy

Name                                                         RetentionPolicy
----                                                         ---------------
b9d20369-3205-4646-b164-92db0afc19c6
alindsaie
anicholsons
7e52a514-eb4b-48ef-8b50-59a671160801
ahesly
arumblie
fe66138c-2a01-41ad-a4e1-5124cd409ac3                         Default MRM Policy
abarclaye
amurrah
c68c5de3-4373-4b81-9e58-dbee16a60eac                         Default MRM Policy

[#6]

I listed all the retention policies on the server.

PS > Get-RetentionPolicy

Name                      RetentionPolicyTagLinks                        Guid
----                      -----------------------                        ----
ArbitrationMailbox        {Never Delete, AsyncOperationNotification,     2023c2c4-165e-43b8-ab09-553352c21db7
                          ModeratedRecipients, AutoGroup}
Default MRM Policy        {5 Year Delete, 1 Year Delete, 6 Month         e8244c40-7f0c-405d-99d5-62be070115a1
                          Delete, Personal 5 year move to archive...}

[#7]

Vasil, I realized I can apply this policy to all mailboxes in the Exchange Admin Center. Just select all mailboxes and select Mailbox Policies. This opens up more options to select which policy to apply.

So think I can take it from there.
Thanks for leading me in the right direction.