I intended to have Derkeethus as my primary follower. I got him to join the blades and everything went well, but when I took his longbow from him to upgrade it, he doesn't seem to equip it when I give it back to him. He doesn't have a bow on his back, and during battles, he pulls out a hunting bow out of nowhere and random arrows. He's using the upgraded sword that I gave him just fine, so why won't he use the bow?

This is a known issue with bow-using companions. (Possible bug?)

Aela the Huntress does it too. You could get her a legendary quality daedric bow and she'll still pull a hunting bow out of thin air to use.


http://elderscrolls.wikia.com/wiki/Aela_the_Huntress

I've noticed that it applies to any follower who comes with a default bow. If you're on PC, there is a fix listed there using the console you can try.

It's a big with bows that affects most followers. Not sure how to fix it. Happened to Sven too. Maybe if you disable and enable them if you're on the PC?

Playing on 360. Oh well. I'll just keep the bow on his person and hopefully they'll patch it next month.

You can still give good quality arrows to increase his damage a little bit at least.

You only need to give him one of the good arrows - he won't run out. And you can farm corpses for those arrows to use yourself as well.
That doesn't work either, at least with Lydia.

On the PC you can force them to equip a weapon, but if you do so they won't switch back to melee weapons until you use the command again (unconfirmed).

Part of the problem is that they seem to use the baseid for a weapon to determine its value instead of its refid (which includes smithing upgrades and enchantments).