Strange iMac behavior ---> White screen at startup & other problems, restart seems to fix things.

[Chakravartin]

hal wrote:
[quote=steve...]The last few days I've been getting a blank white startup screen on both monitors. I get the Apple logo but when the progress bar gets to about 33%, everything goes white and freezes.

Exact same thing happened to my 2012 mini running 10.10.1 on an external SSD via USB3. There isn't supposed to be a progress bar on a standard boot.
Yosemite displays a progress bar while it starts up.

There's no way to distinguish a safe-boot from a normal boot anymore until you get to the login screen and see the "safe boot" message in the corner of the screen.