Kutools stalls if detaching more than 3 email attachments

Question

I am trying Kutools for Outlook, and having a problem.
I use Outlook 365, with Exchange 365. When I tag more than 3 messages to detach the attachment from, Kutools for Outlook seems to stall out on the 4th email. I've let it run overnight, and it is still processing in the morning. I end up having to end task outlook and start again. Nothing else is running.
Is this to be expected? I am trying to detach a folder of emails with 30mb attachments. I have even stepped up Outlook's priority to high, to try and help it. If I select all of the emails, then 'detach all', after 2-3 emails, it just sits.
Is this because it is trial software?
HELP!