Frozen uploads using Mac 10.10.5 and Arduino IDE with Arduino Uno

Hello! I'm a newb and have been having a very frustrating time with inconsistent sketch uploading from the Arduino IDE to my Arduino Uno.

I've spent over an hour researching the forums and googling to find an answer, but I'm having no luck.

I get intermittent upload errors, but I can eliminate the errors if I reselect my port from the tools menu. However, once I eliminate the errors, the upload process hangs up. I've been waiting over 30 minutes for an upload of a tiny program. Surely there must be something wrong?

Can anyone guide me on how to resolve this? While I wait for help, I'm looking into using a command line tool instead.

Kind regards and thanks!
sjenkinsdc