[OS X TeX] texshop fails to change pdf

[Richard Koch]

Zbigniew,

X11 is now handled by a third party. When you upgrade, the Mac
removes X11, replacing it by a stub which tells you how to upgrade it,
so you'll eventually upgrade X11 as well.

There are two ghostscript binaries, gs-X11 and gs-noiX11, one with
X11 support and one without. The actual gs binary is a symbolic
link to the appropriate actual binary.

If you used to have X11, gs is likely a link to gs-X11. But after you upgrade,
X11 is gone and gs-X11 doesn't work.

There are two solutions, and you did one of them:

1) Change the gs link to point to gs-noX11

or

2) Install X11

Dick Koch