General Troubleshooting Guide

While creating new AI and testing I figured out and isolated many issues that you may encounter and what you can do about any issues you have in your game.

Basic Troubleshooting:

NPC's simply disappeared and gone from the world?
1. Usually to do with NPC edits to meshes or a missing master file. Uninstall/reinstall mod or verify game cache.
2. It could be a conflict with AI or another NPC mod keeping them at their default location most cases.
3. Too many meshes on the NPC?

Save related issues:
Signs your save is "bugged" NPC's are dead silent and do not do random radiant scenes anymore. NPCs might be getting stuck somewhere or have weird behavior.

1. Updating ESP-FE mods that added more Form ID's?
2. Mod scripts baked in the save.
3. Removing mods that have permanent alias' active in the save.
4. Magic sound on the character looping can sometimes happen usually edits to the weapon draw sound.

Infinate load screens:
Most internet articles simply say to add more "Memory Allocation" or simply reinstall the game.
1. Installed a mod that requires a patch or another requirement.
2. You somehow reached the maximum ref limit or went above your VRAM limit (memory). 

Startup CTD:
1. Missing a requirement or unchecked master file for a mod.
2. Your game .ini files are messed up. Restore them by simply deleting them and launching the game launcher.
3. ENB conflict (also usually related to .ini configs)

CTD/Freezing in game world:
1. Major conflicts between mods.
2. Animations can cause the game to crash under certain conditions (same with too many effects at once)
3. Broken navmesh even if the mods are not conflicting. Reinstall game or verify game files to fix. This is usually from errors in mods or in self made patches.
4. Script memory leaks (Survival mode + Footprints + Wet and Cold is the main culprit combo for me)
5. Nothing related to Skyrim at all, it's your graphics driver. I got PTSD in Helgen from Alduin landing after the tower CTD.


AI Related Troubleshooting:

There are somethings the AI can do that will break everything including quest initiated behaviors. This is due to how the NPCs utilize the default AI, If that is altered incorrectly they will break and stand still forever.

NPCs are stuck standing still:
1. They are outside of navmesh or blocked from getting somewhere.
2. They are being locked in by a quest scene that is running.
3. The package data is not setup correctly. This will result in borken AI.

NPCs Branch and procedure conditions:
I have better experiences adding conditions on the Procedures than on Branches.
Conditions on Main Stacked sequence branches seem to work fine.

NPCs Looping animation on furniture:

• Using the vanilla sandbox multi location templates remove the first two sequence and random branches with all the simultaneous procedures.
• To fix the looping in your AI packages try to add a wait procedure (while sitting or "getfurnstate") for a duration float between 25-60 to prevent the sit/stand looping animation.
• If energy is not setup in your sandbox packages they may also loop?
  

Looping on Wall Lean Markers and Chairs can occur due to how procedures are setup. This can be fixed by adding conditions for the procedures to prevent the sit loop.


NPC Scenes:
They might be stuck, before or after the scene. Bumping into them usually fixes them.
In other instances if there is a quest that is also pulling in a NPC related to another scene it could break that quest.
Or just a bug that can happen: https://en.uesp.net/wiki/Skyrim_talk:Maramal

NPC don't interact with each other:
Added a new Branch node to an existing SM Event Node but didn't enable Shares Data.

NPCS suddenly become hostile to the player:
Conflict with AI Data for Confidence and Aggression levels.

NPC lip sync is off, lips not moving & floating into space:
1. Approaching the NPC AI limit of the game.
2. A mod is missing lip files for new dialogue.
 See the Engine Fixes mod for a fix.

I can't say anything about all the custom followers that have custom AI built in. They are usually separate from anything else; Utilizing their own quests and scripts.

NPC troubleshooting & AI related console commands:

• IsScenePlaying *SceneID* -Returns true if the scene is playing.
  

• GetQR or GetQuestRunning *QuestID* -Returns true if the quest is running.
  

• GetCurrentAIPackage -will return the package type that is running.
  

Here is what the return value means: https://www.creationkit.com/index.php?title=GetCurrentAIPackage

• TAI -Toggles AI processing on selected NPC.
  

• ResetAI -Attempts to reset the AI of the selected NPC.
  

• Enable/Disable -Disables and Enable a reference. Kinda like a refresh.
  

• RecycleActor/Resurrect -Complete reset of the NPC.