User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0 SeaMonkey/2.53.1

Steps to reproduce:

Download and run SeaMonkey 2.53.1 installer on Windows 10 64-bit

Actual results:

Cylance blocked it during download
Waived the installer in Cylance
Windows won't elevate an unsigned executable, so still fails
Elevation block is not Windows default behavior, but likely to be enforced by group policy in an enterprise environment. Lack of digital signature may contribute to Cylance quarantining the installer. I was able to work around both blocks at work; no problems at home where the system is less locked down.

Expected results:

New version gets installed