Freezes during Computer Check

I just purchased and installed TTP 11 and upgraded to 11.0.1. Each time I run a Computer Check the program freezes while testing the File Structures, specifically the Snapshot Metadata Tree. The entire computer is frozen and I must perform a hard shutdown. My system is running Mojave 10.14.3. Also each time I start up TTP 11, I get the message "TechTool Pro 11 is trying to install a new helper tool" even though I have repeatedly performed this action.