When running on the path from Anvil in the gold coast area the game crashes where there's an Ayleid rune to the right when going down the hill. It only happen when I have the UOP loaded.

what version of UOP are you using?
any other mods in your LO that change that area?
Pacific Morrowind

The supplemental patch. I found a report of the crash on the tes nexus page too.

I know it's the UOP because it only happens when I have it enabled. I double checked.

I also disabled most of my mods when I was trying to find out what was doing it. There's no other mods changing that area.

yes but correlation is not necessarily direct causation.
In this case it could easily be that you have X mod enable that is changing something in that area which when combined with the UOP is triggering that crash... do you have any mods active in that area?
Pacific Morrowind

Now I tried it with no mods activated except the UOP and Alternative Start by Robert Evrae. I started the game out in Anvil to see if it still happens and it does.

Need far more definitive proof of a problem than that, since I know the ruin you're talking about and pass by it on a regular basis. UOP + tons of mods. Including the same alt start mod.

BTW, there's a pretty good chance this is due to the Maiq AI bug. That won't go away by removing mods either since he's a vanilla NPC.

So if I wait for Maiq to leave the area it will be safe to go through without CTD?

I have the same issue except it happend at the crossroad to Kvatch. It only happens with hotfix 325 and 326, UOP 320 by itself is OK. I have tested the heck out of it and can only determine it has to be hardware related specific to my computer.

I tested with only vanilla GOTY and UOPs and skip turotial esp. No other mods.
I tried on Win XP 32 bit and WIn 7 64 bit.
Tried different video drivers.
Switched hard drives
Checked memory.
Tried without Microsoft updates, then with updates.
Tried with and without Maiq patch

I gave up and am sticking to the 320 UOP release only and pray this is not an issue for some other mods. Short of a new computer, nothing else I can do.

I have an ATI 4870 with 1GB VRAM
Dual core processor at 2.66
4 GB RAM
Running Win7 Pro 64 bit

Did you ever try with the ESP from 3.2.6, but none of the meshes/textures?

Yes. It is deffinetly the 325 and 326 esp files. Meshes/textures are fine, tried them without the hotfix esp files. I was hoping someone had 321-324 to see when the problem starts for me but no luck finding them. IT HAS TO BE A COMPUTER ISSUE even though this OP is the third one (including me) who has posted a similar problem. Since everyone else works fine, I can draw no other conclusion.

I just tried on my laptop in a Virtual Machine, same problem. Now my thinking is the oblivion.exe. I have GOTY. Or it is a bad hotfix file on tesnexus. I downloaded it 5 times.

I guess I need to go back to see if I can find the culprit again. My next test tonight will be to install the original Oblivion CD, do the official patch. Then try the UOPs. After that, I don't know where else to test.

So did you test it yet?

Yes, now I can say I AM DONE without finding answer. I have the same issue on my laptop. I have the same issue installing from the ORIGINAL Oblivion CD and not GOTY. So the only common denominators are ME and the downloaded hotfix (downloaded 5 times on different computers). I suspect I am jinxed.

As someone once said, when you exhaust all possibilities, whatever remains, however unlikely, is the truth (or something like that).