IN ALL THEYEARS PLAYING OVERSEER THERE WERE NO INVISABLE DROIDS,
THE ALT+ D NEVER WORKED FOR ME EITHER ONLY ALT+F FOR GIDEONS GALLERY

They're not supposed to be invisible but they're definitely supposed to be there, both the hint system and the game itself talks about them quite a bit.
Good to know that alt-D never worked though.
Ok, with a bit of luck I was able to blindly get through cell block A, and am now in Cell Block C where there is a droid that doesn't crash me when it catches me and is visible, leading me to believe this is a problem specifically with Cell Block A.

the first block walks along the ground, the second block do the ground & also above.
this might help you - http://www.unofficialtexmurphy.com/casefiles/overseer/walkthrough/day8/day_eight_1.shtml

there are no invisible droids, cell A follow behind at a safe distance, cell c - droids go down & then up - wait for it to go back again before darting out, always go from behind. save often & just go up a few cells & then go in a cell till you see it go past again & then follow behind.

Right, that's what I'm saying. I intentionally tried to die by getting too close to the droids, and it didn't reproduce the crash- I got the normal death sequence. The point of this is that the droids, visible or invisible, are not likely the source of the crashes. Just keep saving often and eventually you'll get through the glitch-y area.

I found the same problem, I think if I recall similar to EatMoreBread. Once you're past that area into Cell D it seems to go away.
All in all this was the only problem with this game. An otherwise classic for fans of the genre,

My experience in Alcatraz:
Alt-d is removing the droids, and it isn't droids that crash the game (because if I just stand in one place, it never happens. My _guess_ is that either a piece of scenery or a sound file that is associated with a piece of scenery is corrupted. Cell block A is roughly U shaped, with a row of cells back-to-back in the middle. The game crashes if (roughly) the middle of that row of cells comes onto the screen. This seems to be true from either side of the U. If I stare at the outer walls as I move around, it doesn't crash. As soon as I get the middle of that row in view, it crashes. Makes finding the barb wire a little tricky, but once you know it, it helps you get through.
I also found this page that has some RSX tips at the bottom. Haven't had a chance to try them out yet, so I don't know if they'll help, but thought I'd pass them along. Oh, and the RSX configuration tool is installed, it's just installed in its own program group, not in the Overseer group.

I had absolutely no problems in the game (crash-wise) until I hit the Alcatraz area. Then the game would constantly crash out on me. (I must have crashed a few dozen times.) I would tend to agree that there has to be something corrupted or something as it was only if I looked in a certain direction or ran through an area. (I think it was only happening in Cell Block A and B.)
Otherwise the game ran just fine (Windows 7 x64) and now after 12 years (I bought the game on it's release date, however never finished it), I can now say that I did indeed finish ALL 5 of the games!

I am also having the same issue with the game, Alcatraz crashes as soon as the center row of cells come into view. It is _very_ frustrating.
It feels a little disingenuous to label this problem as solved with "trial and error and lots of saves"

Be Seeing You,
Fallorn

Agree. The crash issue with this game is definitely not "solved". It's a bug, plain and simple. The staff at GOG really need to fix this.

I never got these crashes until recently, but i think its the area where the construction barriers are. I tested it out & found once I avoided that corner no crash. Actually you do need to go around that corner just walk straight to the cell door.