I have an object which is accidently got animated. I have other objects in the scene but only that particular object is moving up and down as I scroll timeline. I can see an orange line under timeline but I can not see any keyframe. I tried to delete keyframes by several ways but no use and that orange line is also not disabled. I checked other objects which are not animated and they don't have that orange line in timeline.
This yellow line represents some type of baked movement like rigidbody , or a constraint , to have a look if this is the problem , you can click on the Physics properties tab 2nd block from the modifiers , their if you see a rigidbody constraint , you need to click the cross to remove it and then start your timeline from the first frame .