Clearing "Installed product key successfully message" through cmd line

I'm deploying our Windows 10 company image through MDT. One of the steps i do is enter the windows key through a command line custom task. The problem I run into is that I keep getting the "Installed product key successfully message" dialog box to come up which stalls the rest of my task sequence and forces user intervention.


The command line I'm using - which I thought would prevent any confirmation boxes - is:

slmgr.vbs -ipk XXXXX-XXXXX-XXXXX-XXXXX-XXXXX /VERYSILENT /SUPPRESSMSGBOXES

Unfortunately this doesn't seem to work. Does anyone have any suggestions on how I can clear this message automatically, suppress it from even popping up or if I'm doing something wrong, what the correct command is?

Any help would be appreciated.

Thanks

I'm not seing the /verysilent /suppressmsgboxes in the slmgr /? help window.

What about adding '>C:\temp.txt' without the quotes to the end to dump the message to a text file then delete the text file?