When You See Deleted Items-null

It often appears due to one of the following issues:

1. Corrupted Folder Mapping

If Outlook’s local cache (.ost file) or the folder structure syncs incorrectly with the Exchange server, it might create a placeholder subfolder with the name null.

• This happens when the client cannot resolve the folder ID during synchronization.

• It’s essentially Outlook saying, “I tried to put it in a folder, but that folder ID resolved to nothing.”

2. Third-Party Add-In or EWS (Exchange Web Services) Bug

Certain add-ins or synchronization clients (mobile apps, archivers, or antivirus email scanners) can trigger malformed folder paths.
When they try to delete or move a message but pass an invalid folder ID to Exchange, the API sometimes falls back to a “null” folder name.

3. Server-Side or Mailbox Corruption

If the mailbox folder hierarchy has a corruption entry in Exchange (visible through Get-MailboxFolderStatistics PowerShell command), Exchange can sometimes show phantom folders like:

These are ghost subfolders created during recovery or inconsistent sync events.

🧹 How to Fix or Investigate

Option 1: Use Outlook in OWA (Web App)

Check Outlook Web Access (e.g., https://outlook.office.com).
If you don’t see the null subfolder there, it’s likely just a local Outlook cache problem.

✅ Fix:

1. Close Outlook.

2. Delete or rename the .ost file (it will resync on next launch).

3. Reopen Outlook — the folder should disappear.

Option 2: If It Exists in OWA Too

If the null folder actually appears in the online mailbox:

• Use PowerShell to inspect it: 

  Get-MailboxFolderStatistics -Identity user@domain.com | Where-Object {$_.Name -eq "null"}


• You can then delete it safely using: 

  Remove-MailboxFolder -Identity "user@domain.com:\Deleted Items\null"


  (requires Exchange Online Management module and admin privileges)

Option 3: Repair the Folder Mapping

Run Outlook’s “Repair” tool under: 

🔍 TL;DR

Deleted Items\null\ is not a valid Exchange folder.
It’s a ghost or corrupted subfolder, usually caused by:

• Sync/cache corruption, or

• A buggy add-in or EWS client.

Deleting or repairing the local cache or cleaning the folder via PowerShell typically resolves it.