PowerShell: Force Outlook to Compact On Exiting

Forcing Outlook to return free disk space to RDS nodes upon user exiting would be desirable to keep server storage in check. Also, deleted messages would be completely purged once this is set. Therefore, such feature would only be required on certain use-cases.

Please note that time it takes Outlook to shutdown will be increased. If Outlook is forced closed during the compaction process the data file could become corrupt. When using this registry key, one should not set the option to empty deleted items on exit as that would significantly expanding program closing lead-time.

# Force Outlook to compact pst upon closing
$officeRegKey=(get-childitem 'REGISTRY::HKEY_CURRENT_USER\Software\Microsoft\Office').Name|?{$_ -match '\d+\.\d+'}
$outlookRegKey="$officeRegKey\Outlook\PST"
$outlookCompactConfigKey='PSTNullFreeOnClose'
$outlookCompactConfigEnable=1
# set-itemproperty -Path $outlookRegKey -Name $outlookCompactConfigKey -Value $outlookCompactConfigEnable
[microsoft.win32.registry]::SetValue($outlookRegKey, $outlookCompactConfigKey, $outlookCompactConfigEnable)