I have an issue where NPCs will not properly equip or use their weapons. When an NPC should have their weapon holstered, they will idle holding it in one hand. When they come under attack, instead of equipping and using their weapon they will run towards the enemy but are unable to fight back. Their faces will look like they are shooting back but they will do nothing until either the danger has passed or they die. If the NPC is essential then the weapon will sometimes hover over their backs and they will still not be able to fight.

https://imgur.com/a/8yIo9

This only happens to friendly NPCs randomly. So far the only way to fix the issue and force the NPC to properly equip and use their weapon is to disable - enable them via console. However, this is only a temporary fix and there is a chance that when encountered again, the NPC will be glitched again.

I have gone through and disabled all my mods one at a time to isolate the issue, but so far nothing has helped.

Load Order

Fallout3.esm
Anchorage.esm
ThePitt.esm
BrokenSteel.esm
PointLookout.esm
Zeta.esm
Unofficial Fallout 3 Patch.esm
Project Beauty.esm
Project Beauty- Broken Steel.esp
Project Beauty- Point Lookout.esp
PCIdles.esp
Auto Aim Fix v1.1.esp
FPS Grenade Hotkey.esp
FPS Grenade Hotkey - Zeta addon.esp
1PipboyPDA.esp
Gore_No_More.esp
Realistic Death Physics.esp
Fellout-pipboylight.esp
Fellout-Full.esp
Fellout-Anchorage.esp
Fellout-BrokenSteel.esp
Fellout-PointLookout.esp
Fellout-Zeta.esp
NoTracers.esp

Some questions, since you don't specify and might make a difference.... Does this happen with vanilla or non-vanilla weapons? Do you give them ammo with their weapons?

It happens with vanilla weapons and whatever ammo they normally spawn with. I don't have any mods that specifically affect weapons or weapon lists (Unofficial Fallout 3 Patch might, not sure).

When I disable and re-enable them they will equip and use their weapons as normal.

Sounds like a package issue. I'll say up front it's been a ridiculous amount of years since I've played F3. I'm not seeing anything in your list that sounds like it would logically edit those, though, unless PCIdles affects NPC's too.

If it were me in that situation, since your load order is small, I'd disable mods one at a time and test for a while to see if I could pinpoint the cause.

I thought that PCIdles would be the issue too, but after disabling it and making a clean save the problem persisted.

What do you mean by "package issue"?

Package is the term used to describe a set of rules that defines NPC activity, the conditions that cause them to react and the commands they execute in response to them. There are idle packages, wait packages, follow packages...

That leads me to another thought, is this always the same NPC's? Are they vanilla or added by a mod? This only happens to companions, but not other NPC's?

I recently reinstalled Fallout 3 and the only settlements I have discovered are Megaton, Big Town and Arefu. The glitch affects any NPC with a weapon from either of those places, from potential companions to named NPCs to unnamed Megaton settlers. I only noticed the combat bug when I came across Crazy Wolfgang fighting raiders outside of Arefu. Both him and his guard were both glitched and unable to shoot back.

I don't have any mods that adds NPCs and as far as I know, none of the mods I am running alters behavior in vanilla NPCs.

At this point I don't know what to tell you. You could open up your load order in F3Edit to see if anything jumps out at you in the NPC/package records or start deactivating mods until you figure it out.

I checked through my load order through F3Edit and nothing jumps out at me for items affecting NPC behavior. Both the Unofficial Patch and Project Beauty made changes to certain NPCs, but the problem I'm having seems more widespread than either of those.

Even disabling all mods and making a clean save didn't fix the problem. NPCs will still walk around glitched, and they will glitch again after "fixing" them via disable / enable.

Even Google search is coming up empty. I have tried every combination of search terms I can think of, but without a specific commonly accepted name for the glitch I'm just sorting through posts by people with other problems.

If even disabling all your mods doesn't fix it, it sounds like it might be time for an uninstall. That's pretty much all you haven't tried at this point. If you've installed through Steam you can try to verify your game cache first.

Of course make backups of everything, including your ini's first.