cannot delete dumpster files from public folders - PF migration process

Question

Hey, I want to migrate my Exchange 2013 public folders to Exchange online. I noticed that I had a few folders that contained characters that were not allowed in the migration, so I renamed them. After running the Export-ModernPublicFolderStatistics.ps1 script again, i saw that the folder names are still in the dumbster_root folder present and causing an error. So I tried to use MFCMAPI to delete these files, but could not. Every time i click on deleting folders, nothing happens (no even the pop-up menu to force delete is showing). Is there any workaround for dumpster files in the Export-ModernPublicFolderStatistics.ps1 script? I appreciate any thoughts.

Answer 1

Hi @Semjon Paul,

Welcome to Q&A! 

To help us better understand your problem, please kindly share some screenshots:

Screenshots of the error message encountered when executing the Export-ModernPublicFolderStatistics.ps1 script

• Screenshots of the MFCMAPI interface when attempting to delete the problematic folder

I’ve replicated this scenario in my test environment (Exchange server 2019) with the following results.

a. Created two test folders: PFSUB01 (valid naming format) and PFSUB\02 (invalid format with backslash).

Both folders appeared in the dumpster_root immediately after deletion. Manual deletion attempts were unsuccessful.

b. Successfully executed the export script.

c. The generated CSV only included the valid folder (PFSUB01), with no data for the invalid folder (PFSUB\02). It indicates the export script automatically filters out folders with invalid naming conventions.

Since Exchange Server 2013 is now out of support, we'd like to understand whether you plan to maintain a hybrid environment or transition to a pure cloud solution.

If you choose to keep the hybrid environment, we recommend first upgrading your Exchange Server to the 2019 version before migrating public folders to Exchange Online.

Alternatively, if you prefer a more immediate solution, you can migrate public folders directly using Outlook PST export. Detailed steps for this approach are available in Microsoft's official documentation: Batch migrate Exchange Server public folders to Microsoft 365 or Office 365 | Microsoft Learn.

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Answer 2

Hello and first of all, thank you for your detailed answer.

This is what my Exchange server is showing:

These folders are located in the DUMPSTER_ROOT folder, while your deleted folders are located in the DUMPSTER_EXTEND folder.

After I failed trying to delete this entry, I moved on to the other error entries, and somehow I was able to delete all of them except for two ("Bündnis90/Die Grünen" and "Radabeul/Coswig"). But after refreshing the view all folders were back, so I guess they are not deletable.

For context:

I am aiming to shift completely to the cloud after this migration and a batch migration is not an option for me, because my PF is like 80gb large.