During my last play through I had http://www.gamesas.com/bgsforums/index.php?showtopic=1073298&hl= in certain locations, which was fixed by unchecking Unofficial Fallout 3 Patch - Broken Steel.esp. After that I http://www.mediafire.com/?z3qmlzyzomy and started using it again and didn't have the problem again.

Restarting with a different mod list (basically MMM added), everything has been fine but now I have repeatable ctd's on saves again, this time south of the Scrapyard. One thing I've noticed is that I get a strange graphical artifact with one of the Raiders that are closeby - it's a blue square that flashes on and off. Checking his inventory, he had just a Sledgehammer, Raider Sadist Armor and some Bottle Caps so I'm unsure on what that might be - and if it is connected to the CTD issue at all.

The game is patched to 1.7, it CTD's with quicksaves, hard saves and the CASM autosave. Here's my mod list:

Fallout3.esm
Anchorage.esm
ThePitt.esm
BrokenSteel.esm
PointLookout.esm
Zeta.esm
Unofficial Fallout 3 Patch.esm
Hairday.esm
StreetLights.esm
Mart's Mutant Mod.esm
DCInteriors_ComboEdition.esm
Unofficial Fallout 3 Patch - Operation Anchorage.esp
Unofficial Fallout 3 Patch - The Pitt.esp
Unofficial Fallout 3 Patch - Broken Steel.esp
Unofficial Fallout 3 Patch - Point Lookout.esp
Unofficial Fallout 3 Patch - Mothership Zeta.esp
DarNifiedUIF3.esp
StreetLights - Wasteland.esp
CASM.esp
GalaxyNewsRadio100[M].esp
BusworldV1.05d.esp
Mart's Mutant Mod.esp
Mart's Mutant Mod - DLC Anchorage.esp
Mart's Mutant Mod - DLC The Pitt.esp
Mart's Mutant Mod - DLC Broken Steel.esp
Mart's Mutant Mod - DLC Point Lookout.esp
Mart's Mutant Mod - DLC Zeta.esp
Mart's Mutant Mod - No Corpse Flies.esp
Mart's Mutant Mod - Zones Respawn.esp
dD-No Screen Blood.esp
Dread Dogmeat.esp
Mark and recall.esp
Ammo Box Respawn.esp
medkit and toolbox respawn.esp
Arwen_XPR.esp

Guess I'll try to disable all the unofficial patches (which was one recommendation in the other thread) and see if that helps, but does anyone have an idea what might cause this?

Hmm, I can just come up with a default advice: Disable MMM and try to save. After that you can enable it again. This usually fixes those kinds of errors for me, though yours might be caused by something else.

Just out of the blue, try disabling street lights -wasteland.esp and see what happens

1. Tried disabling all MMM plugins - still crashed.
2. Tried disabling all unofficial patches - still crashed.
3. Tried disabling Street Lights - Wasteland - still crashed.

I think I'll try disabling the unofficial patches and wait for a respawn and return to the area and see what happens.

EDIT: Loading from the same save the game still CTD'd on save after returning to Megaton, whatever that means. Anyway, I loaded from an earlier save, returned to Megaton, uninstalled the unofficial patches, waited for a respawn, returned to the same area and everything seems fine. Of course, this doesn't prove that the unofficial patch caused the issue, but I'll continue w/o them anyway for the time being.