I am in Day 2 of an Intel Fortran trial. I was going to try building an old application with ifort 20, but ran into a link problem that I have documented as another topic. The earliest version available is 18, and I once built the application using that, so I decided to give it a try. I installed ifort 18 using my serial number, which was accepted. But when I try to use the compiler, I am told that it can't find the license file.
All licensing questions need to go through https://supporttickets.intel.com/?lang=en-US I am not sure how the trial versions work, but normally when you enter the serial number during install, it copies a license file onto your system.