When trying to "unembed" an image in an AI file, it is very common for the software to completely stall when attempting to navigate to a save location. I have already run this problem through Apple (re:finder) and they claim that it is not a finder issue, but based in the selected software. Upon force quit and relaunch, the process will succeed. As a graphics professional, I have used this command many times daily, for 20 years, and have never experienced an issue until now. Honestly, I have no idea and cannot find any resources to reference.