Clear Old Public Folder Database Settings on Mailbox Databases in Exchange 2013+

clear-pfdb-on-mbxdb.ps1

import-module activedirectory
# Substitute correct values in place of * and com below.
cd "AD:\CN=Databases,CN=Exchange Administrative Group (*),CN=Administrative Groups,CN=*,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=*,DC=com"
get-item * -Properties msExchHomePublicMDB | `
  foreach { 
    # Show name of mailbox database
    $_.Name; 
    if ($_.msExchHomePublicMDB -eq $null) { 
      "NULL PF DB" 
    } else { 
      # Show name of public folder database (legacy)
      $_.msExchHomePublicMDB; 
      # Clear the legacy public folder database setting on mailbox db
      set-adobject $_ -Clear "msExchHomePublicMDB" -verbose 
    } 
  }