Since upgrading to Yosemite 10.10.3 my Photoshop quits every time I try to open a file. Anyone having the same trouble

Which version of Photoshop are you running and what's the error message if any?

have you installed the java runtime update.

Java for OS X 2014-001

CS 6 or Photoshop 6. CS6 is version 13, Photoshop 6 is super ancient history.

Either way CS6 should work in Yosemite but not officially supported by Adobe any longer.

Are you trying to navigate to a location that is not there like a disconnected drive?
Photoshop tries to remember the last location you opened from

• close photoshop
• open Macintosh HD:Applications:Adobe
• find the Photoshop folder or photoshop.app inside the folder, wherever you installed it
• hold down ctrl+opt+shift+cmd and click on the photoshop icon as you are holding these down
• when the prompt comes up to reset preferences click okay

you can't do this from the dock icon or an alias btw.

if that does not work

• create a new admin account,
• boot to that account
• run photoshop,

if it works there is a problem with your old account and possibly corruption.