In an attempt to leverage my existing .NET skills, I started working on learning MonoTouch and MonoDroid. I tried following the simple HelloWorld tutorial on the documents section of MonoTouch and kept getting a random error during any build:

mtouch exited with code 98

This is a really good example of bad user experience. The error is extremely cryptic and tells the user nothing. I tried searching for documentation on error codes to no avail. Finally I stumbled upon the build output tab (which is hidden by default, unlike Visual Studio) to find a bit more useful information:

License file is missing. Please activate MonoTouch.

Looks like the IT team didn’t activate the license properly on the Mac they provided me but having this error description shown in the error list would have saved me 3 hours of hunting.