Comment 5 for bug 964331

I'll try to explain a bit better. If you have two drives and neither drive has adequate free space (as little as 4.4GB for Ubuntu I believe) and you select Use entire drive another window opens that'll allow you to choose which drive you wish to use.

But if you have two or more drives and there is adequate free space on any drive (could even be an external drive or flash drive/card), and you select Install alongside then the installer just proceeds to use that free space. The only way to differentiate what is going to happen is the fact that the button in the lower right hand corner should change from "Continue" to "Install now".

If it says Continue when you click on it a new window should open allowing you to select which drive is going to be used and allowing you to move the "slider" to adjust partition size.

If it says Install now then as soon as you click on it the installation begins using the largest continuous available free space.

Quite simply, if it says Continue you should expect to be offered more options, but if it says Install Now it really means just that. Please see:

https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/766265/comments/34

Does that help explain things at all?