PureData wouldn't open, kept crashing on startup every time. Tried various stuff with Terminal but without luck.
So out of desperation I looked at the package contents and threw away the .plist.
Now it works fine but the top left of the screen where it normally shows the name of the application says "Wish" and the icon has changed from the PD icon to a piece of paper with a pencil, brush and ruler on it.
Any ideas?
Do I just need to re-install?

@nuromantix Wish should be open, but should be hidden in the background. It deals with all the tk/tcl code and Pd needs it in order to work (and talks to it through a network port).....
Pd is still not opening properly if you do not get the Pd terminal window. You could try typing "open pd" or "exec pd" into that "wish" terminal window.
David.

PureData runs perfectly and the PD terminal window is there.
Simply the application name now appears to be Wish and PD files don't automatically open in PD because they don't see it. You have to open them from PD's file menu.

It stopped working completely so I did a new install of PD extended, but it still instantly closes as soon as it opens.
Vanilla works fine.
The only thing that has changed on my computer is that I have recently installed Vanilla as well as Extended. Could there be some kind of clash between the two?

Never mind, fixed it in the end with cmd + alt + Q, had to try several times to press it in the tenth of a second or so available before PD quit by itself!

Note that extended is no longer developed so it is very likely to be buggy with newer OSes, while vanilla is actively maintained and takes care of OS changes. Better use vanilla, since now it's super easy to install external libraries with the deken-plugin which is biult-in the latest vanilla.

Yes I mostly do but sometimes Extended is such a time-saver when you want to try out an idea.