Troubleshooting Public Folder Deletion Issues in Exchange Online

This post has been republished via RSS; it originally appeared at: New blog articles in Microsoft Community Hub.

Public folders provide a way to collect, organize, and share information with other people in your organization. They can help users organize content in a deep hierarchy that's easy to browse in Outlook and Outlook on the web (OWA).

This blog post is here to help admins troubleshoot deletion issues with public folders, with a focus on the following scenarios:

  • A user with sufficient permissions (for example, folder Owner) is unable to delete items within a public folder. After content is deleted using OWA or Outlook, it re-appears within a few seconds.
  • A user with sufficient permissions (for example, Exchange administrator) is unable to delete a public folder and its content using Outlook and is getting one of the following errors:
    • Microsoft.Exchange.Data.StoreObjects.ObjectNotFoundException: Could not find public folder Dumpster for \PF1
    • Microsoft.Exchange.Data.StoreObjects.ObjectNotFoundException: The process failed to get the correct properties. ---> Microsoft.Mapi.MapiExceptionNotFound: MapiExceptionNotFound: Unable to get properties on object

These issues can occur when the public folder dumpster is invalid or does not exist. The exact reason for this might not be known, but the issue typically happens after public folders are migrated from on-premises servers using PSTs or third-party migration tool.

What is the Dumpster Folder?

Today’s public folder storage model uses a visible “IPM_SUBTREE” part that contains public folders and their content, and a hidden area called the “NON_IPM_SUBTREE” that which contains dumpster folders and other system related folders.


Every content folder has a dumpster folder where deleted items are retained according to the defined retention time. Once the retention time has elapsed, the items are permanently purged.



As illustrated here, deletion of public folder content is really a content move from the visible folder to the dumpster:


Each folder and its dumpster are linked to each other. This link cannot be undone, and admins cannot delete dumpster folders by themselves. When a folder is removed from the public folder hierarchy, its dumpster is automatically removed. The same principle applies to mailbox folders and subfolders, too.

Addressing public folder/item deletion failures

A newly published PowerShell-based tool, ValidateEXOPFDumpster, can help you investigate public folders/items deletion failures. The tool validates the following:

  • Public folder size
    • Public folder content mailbox TotalDeletedItemSize value has exceeded its RecoverableItemsQuota value
    • Public folder size is full
  • User permissions are not synced between public folder mailboxes
  • Content public folder mailbox between the public folder and its dumpster are different
  • EntryId and DumpsterEntryID values are not mapped properly on the public folder and its dumpster
  • Parent public folder dumpster is unhealthy
  • The public folder is a dumpster folder
  • Dumpster folder has child folders
  • Mail-enabled public folder MEPfProxyGuid is “null”

How does the tool work?

Typically, the tool is run with a PFolder parameter specifying the public folder identity as follows:


.\ValidateExoPfDumpster.ps1 -PFolder \pf1


The tool will prompt for affected public folder identity/EntryID if it wasn't provided using PFolder parameter and then it will prompt for Exchange administrator username and password to connect to Exchange Online. By default, the tool assumes that the issue being investigated is impacting to a specified public folder but all users are affected.

If the deletion issue happens only for a specific user, the user’s SMTP address can be provided as follows:


.\ValidateExoPfDumpster.ps1 -PFolder \pf2 -Affecteduser


The tool will generate the public folder validation checks failures and proposed fixes results on the screen and will generate the ValidatePFDumpsterREPORT.txt file, as well. There are other files generated for either logging purposes or for logs to be shared with Microsoft support.

File Name




Information about any issues found

The tool displays what it found, and in many cases, it provides a solution to fix the problem


Information about the reason of tool run failure

The file will display errors encountered during running of the tool and at which stage it failed


All required information about the affected public folder

Shared with Microsoft support if engaging support about this problem

Let’s check the following examples to get more clarification on how the tool works.

Example1: Running the tool on the affected public folder “\pf2” where only one user is affected (user@(domain).com). 


The tool points out two issues:

  • Neither the specified user nor the default user have sufficient permissions to delete items inside the public folder
  • Public folder size has exceeded the Individual Public Folder ProhibitPostQuota value

Example2: Running the tool on the affected public folder “\t” where all users are affected


The tool points out the following:

  • Public folder and its dumpster don't have the same content public folder mailbox
  • Public folder EntryId and DumpsterEntryID values are not mapped properly
  • Public folder size has exceeded Organization DefaultPublicFolderProhibitPostQuota value
  • Public folder dumpster has 1 subfolder

The tool also creates a log file containing all the required information "PublicFolderInfo.xml" to be shared with Microsoft support, if needed, and has provided mitigation for the last two issues.


Special thanks to Bhalchandra Atre and Nino Bilic who reviewed and contributed to this post.

Hazem Embaby
Support Escalation Engineer

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