Let’s say; you’ve downloaded a rig from a website to test out your new mesh to see how it would look when it’s animated. But the problem is, this rig has unneccesary bones that cause problem in Unreal Engine, and you wish to get rid of them, but even though you select the bones you want to get rid of in the outliner, Blender does not delete them. So what’s the solution? What’s the next step to take?
01. Make Sure You’re In Edit Mode
Bones can not be deleted in the object or pose mode. As the first step, switch to edit mode, and while in the edit mode, press “Alt + H” to see if any bone is hidden.
02. Check Viewport Display Properties
In the bone properties window, make sure that bones are not hidden.
03. Check The Layers
In the object data properties panel, make sure all layers are activated. Circles with filling and circles without filling represent hidden/visible layers. Check both layers and protected layers to make sure of that no bones are hidden here.
After all of these actions if you still can not delete the bones you wish to delete, you can describe the issue you’re having in detail and I could try to help you.