PI DataLink Search cause PISDK Registry Key Access is Denied

Dear experts, 

Whenever I press the search button on Excel 2013 Ribbon, PI DataLink menu, this warning of PISDK Registry Key Access is Denied (see attached picture).

However the PI ProcessBook search button has no problem, and the PISDK Utility also has no problem in connecting to PI servers.

I would be grateful if you can shed some light on how to deal with this.

Thank you