Got "APP is not verified" Error on Macs Joshua Chang October 15, 2018 03:41 Follow Go to https://www.tiertime.com/downloads/software/, find the LKD File for MAC V x.x.x.x. Open UP Studio, choose Activate, and then load the LKD file. Related articles UP Studio cannot be installed due to unsigned driver issues. Can not find the printer in the printer list connected to WI-Fi? 3. Print Settings Model Calibration – Vertical Calibration Comments 0 comments Please sign in to leave a comment.