First, unzip the install package.
After clicking next you see a screen the legal text:
You need to accept the software agreement and also tick the box at the bottom:
After clicking Next you will see what's about to be installed:
This can differ depending on what's already installed on your computer. Normally you just click on 'Install' and then you have to wait a few minutes
After clicking 'Finish' you will hopefully see a Mathcad Prime icon on your desktop:
Using the 'PTC Mathcad Prime 18.104.22.168' start menu item or double-clicking on the icon will start Prime:
I go through the steps to install the trial version of Mathcad 15 but in Step 9, I get the error message "A problem was encountered during the MSI installation". I tried to install by being the administrator and then without being the administrator. I got the same error message.
Please Refer article to address the MSI error -