Hi everyone!
Just bought this game off GOG (although I already own the old boxed version) and whenever I try to boot the game, this message comes up and I have to exit. Haven't found anything yet on this subject, so any help would be greatly appreciated!
Note:
I'm using Windows 7 32bit.
I have installed the game in a different path than the default one.
I used the GOG shortcut for the game and the executable in the GK3 directory, same thing.
I haven't used any tweaks, or other files, nor have I edited the registry in any way.
Any ideas?
Thanks!

What was the whole message?

That was the whole message. Everytime I run the game, it starts and before it shows any kind of menu or logos, this box comes up with a red "X" in the corner, and the message "Unrecognized Fatal Exception". I have to click OK, and the game exits.
Oh, I have tried every step that GOG recommends for a problem.

The game has always had issues with installing it outside of its default path. This is usually correctable by manually fixing paths in the registry. The fault probably was with the original installer, so this may not be an issue with the GOG release of the game. Just to eliminate it as a possible problem, check the path in HKEY_LOCAL_MACHINE\SOFTWARE\Sierra OnLine\Setup\GK3

Well, I uninstalled the game and then installed it again, in the default given path, but the problem persists... Running out of options...

Could be you have a program running it doesn't like... check you Start Up manager.

What did you find in in HKEY_LOCAL_MACHINE\SOFTWARE\Sierra OnLine\Setup\GK3 ?

Hey, I have almost the same problem, except that I can run GKIII correctly. Actually this "unrecognized fatal exception" error occurs during a cutscene, during day 2, between 7am/10am and 10am/12pm. I searched and apparently this can be solved by renaming a file (in c:/windows/system32) called mpeg2dmx.ax into mpeg2dmx.ax.old (or mpeg2dmx.old, I didn't quite get it...). But this has been advised to people running GKIII on Windows XP, and this mpeg2dmx.ax file doesn't exist in Windows 7 I think, because I couldn't find it. I found another one called mpeg2data.ax and one called mpg2splt.ax, but anyway I can't change their extension because I need a special authorization from trustedinstaller obviously, and I don't want to take the risk to change an important file. Anyway if that can make the research move on, that would help.
PS : I can stil play, I just have to skip the cutscene when it starts.

This error message used to plague players of the original game release. On the good old days of the Sierra boards, it was probably the most asked question about GK3.
There were two known causes.
One was difficulty reading the CD-ROMs. They were over-sized, which was then a form of copy protection. Some readers didn't like them.
The other was a corrupted BRN file on disk 1 in many copies of the game. Fortunately, the BRN files were duplicated on all disks, so the fix was to copy an uncorrupted version from disk 2 into your program folder. (In fact, it was recommended that you copy all the BRN files onto your hard drive.)
Of course, it's unlikely that any of these issues are the cause of your problem. However, according to the developers who posted on the old boards, the error message specifically means that a game file cannot be read (for whatever reason).

I am receiving the same "fatal exception" message, always at the exact same moment during the cutscene at the beginning of Day 2, 12-2pm time block. The game was working beautifully until this.

It's an old problem but someone may still benefit from this.

Try right-clicking on the actual game icon and run it in Windows 95 compatability mode.

I had exactly the same problem and this worked for me.