[Andrej]

As stated, TeXShop crashes when closing the text window while the PDF output is displayed. This problem did not occur when I first installed TeXShop, but since reinstalling it after doing a backup and restore of my data, I cannot seem to install TeXShop such that it works correctly.

I have tried removing the files "TeXShop.plist" and "TeXShop.plist.saved" from my user preferences, and that did not work.

I searched the internet using various combinations of keywords, but the resulting suggestions were not quite relevant to my problem.

I tried searching this forum using "TeXShop," but that turned up software recommendations, and then using "TeXShop crash," but that gave very random results.

What else can I do?

[bhdz]

Do you use TeXShop on Intel or PPC? It might be relevant. I switched to v.2.10 beta, and I've had no problem so far on my Intel Mac. I also run the gwTex distribution.
Have you tried a complete uninstallof TeXShop?

[Andrej]

My late 2006 copy of MacTeX (with TeXShop included) runs on an iMac G5. There does not seem to be an uninstaller with the package. I just checked.

How do I completely uninstall? Or is this something that I need to look up?

[Andrej]

Well, I just tried uninstalling MacTeX by following the directions at Uninstalling - MacTeX - TeX Users Group as best as I could, but I still have the problem.

Edit: The problem has now been solved. The problem arises with a conflict with a theme called CrystalClear (an excellent transparent theme for 10.4.10) in which the fade transparency transition must be turned off for just that application.

(I told you people that I try to figure it out myself.)