I have Office 16 installed locally from Office 365. Outlook runs locally on local PST files. Yesterday, I started getting "The operation failed. The messaging interfaces have returned an unknown error. If the problem persists, restart Outlook." when I try to empty the Deleted Items folder. I can delete messages but only one at a time. The error occurs even if the folder is empty. I cannot seem to resolve this problem.

Actions I have taken, with no resolution from any of them:

  1. Restarted Outlook.
  2. Ran ScanPST on all PST files until it ran clean using this command:"C:\Program Files\Microsoft Office\root\Office16\scanpst.exe" -file .pst -rescan 5 -force
  3. Uninstalled Office 16 32-bit. Installed Office 16 64-bit.
  4. Ran ScanPST again with the new Office.
  5. Deleted the profile and created a new profile with all email accounts.

I have 4 PST's open but this error only occurs on my primary, the default, account. This all started when I deleted a significant number of duplicate contacts but they are all gone and the Deleted Items folder is empty.

UPDATE: Just checked Event Viewer and found this: "Profile notification of event Load for component {B31118B2-1F49-48E5-B6F5-BC21CAEC56FB} failed, error code is See Tracelogging for error details."


You may be experiencing the error that is described in the article
Windows 10: User Profile Service Event ID 1534 warnings.

The cause is apparently Windows software that was not fully removed by Microsoft in version 1809, and the solution is to remove it manually by registry update. It is counseled to create a system restore point before doing such manipulations.

The procedure is:

  • Download ExecTi
  • Use ExecTi to open regedit as TrustedInstaller and navigate to the following two keys :

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileNotification
    HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows NT\CurrentVersion\ProfileNotification
  • Check if the above two keys have a TDL sub-key

  • Export for backup and delete the TDL for each key
  • Do the same for these keys, exporting and deleting:

  • Reboot.

This method apparently originated from the post New 1809 update now shows this in Event Viewer.

Take all precautions possible, and if errors appear after this modification, return the saved registry data, or restore the created system restore point.


I tried the recommendation from harrymc, and I thank you for that. I even tried Stellar Repair for Outlook which did not help.

In the end, I created a new PST file, copied all the emails over, and exported/imported all the information I could from contacts and calendars. I wasn't able to block/allow sender lists in my case. But, most of what I needed I as able to recover.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.