That's what I get for thinking "I'll upload it before I go to bed"...

The 1.0.0 zip is missing StowIt.xml.

A new version (1.0.1) is uploaded that has all the files needed for the addon to actually do something.

At the moment, if you attack a 1 HP critter it sheaths your weapon after 3 seconds or so, but if you're in combat with a regular mob it sheaths your weapon the instant you leave combat (probably because those seconds are spent in actual combat and not looking at a one-shotted critter).

It's not completely trivial to add a delay though - the API fires an event on entering combat, but not on leaving it, so I have to use that event to set a flag that the weapon should be sheathed once combat stops, and then check an API method whether the player is in combat to be set to "no" to actually trigger the draw/sheath toggle (there's no "sheath weapon" method, just a toggle between drawn and sheathed).

So I'm looking at adding a timer that starts when the API method returns that the player is not in combat and not trigger the draw/sheath toggle until that timer runs out - although that will mean that you'll auto-draw your weapon if you sheath it manually while the timer is running...

AFAIK there's no API call or event to check whether the weapons are drawn or not.

Er, no it isn't.

Be sure you download version 1.0.1, version 1.0.0 doesn't do anything (in fact, I think I'll just remove it from the downloads).

Other than that, the only thing you should need to do is make sure it is enabled (ESC - Add-Ons - Stow It should have a check mark in the box).

Edit: Try the new version, 1.1.0
I've rewritten the check for whether we are in combat or not and added a small timer so you don't sheath before animations have stopped playing (I think that was what was causing your issue).

Please do this:

1. Go to your AddOn folder (should be something like C:\Users\<yourUserName>\Documents\Elder Scrolls Online\<live or liveeu>\AddOns) and delete the StowIt folder.
2. Re-download the addon (version 1.1.0) and unzip it into the above folder. This creates a new StowIt folder.
3. Make sure there's three files in the new StowIt folder; StowIt.txt, StowIt.lua, StowIt.xml.
4. Start the game, log into a character, hit ESC - Add-Ons and verify that there's a check mark in the box next to Stow It.
5. Find a 1 HP critter (a rat, a sheep, a lizard, or something similar) and kill it with a single basic attack.
6. Wait 10 seconds (after the critter dies, you're in combat for roughly five seconds before the timer starts). You should then see your character sheath its weapon(s).
7. You can also find a regular mob and kill it; in that case you should see your character sheath its weapon(s) shortly after the mob dies (as there's no extra delay here, you exit combat the instant the mob dies and the timer starts then and runs for a short bit).

There's no reason the addon shouldn't work for you; it doesn't do anything but listen to an event that fires on entering combat, sets a flag and then checks another flag to see when you leave combat. When this happens, a timer starts running and when that timer is done, the addon toggles the draw/sheath togggle.

Thank you, and thank you for the tip; I've rewritten the addon to take advantage of that function. It now triggers on entering combat, checks once a second if you've left combat, and if you have it sheaths your weapons a second and a half later.