After SN7 installation fails, go to C:\Users\YourUserName\AppData\Local\Temp\ and sort by date. Grab the most recent log file. The log filename looks like MSIXX123.LOG.

Submit the error log in a ticket request for assistance.

Can't find the recent log file, please see here:

https://support.microsoft.com/en-ca/help/223300/how-to-enable-windows-installer-logging

Thanks!