-BlockExecution switch issues

Hi

has anyone experienced any issues using the -BlockExecution switch?

I’ve used it when installing add-ins for Outlook to stop the users from opening Outlook. However I’ve had issues where some users are able to open Outlook before the BlockExecution kicks in? doing some testing there is about a 10-15 seconds delay from hitting “continue” to “Installation in proggress. Please wait…” screen (which is when -BlockExecution kicks in). does anyone have a work around for this issue or can suggest anything?

Cheers!

Ash