Be careful. Sometimes the compiling process runs out of RAM memory and tries to use the hard disk as a swap space, but never actually finishes. I had my computer compiling for more than a day and nothing happened.
To avoid this, make sure that your RAM memory is 1.5 times the visibility matrix that the compile process window tells you.
If your visibility matrix is 40, then you need 60 MB or RAM and so on. Not a problem if you have a good PC