For some reason I can't seem to select a sword that I duplicated from a previous one. The previous sword is still selectable but the duplicated one is not. For some reason blender selects whatever is behind the object. However I dragged a box over it about 20 times and found that it worked once, but it selected everything with it.
Check to see if it is listed in the Outliner. If it is, click on it's entry. If it still won't highlight, check to see if the arrow icon is toggled. Click it to make sure it's not greyed out. This indicates whether an item is selectable.
If the Cursor Icon is not displayed, expand the Restriction Toggles by clicking on the sieve icon in the top right of the outliner and enable it.
There are some possible reasons:
- You duplicated the mesh in edit mode, but the object is still the same. See if your swords appear as separate objects in the Outliner.
- Your duplicated object was somehow marked as unselectable. See if the pointer icon is active in the Outliner.
- There's one or more objects in front of the one you're tying to select. Try to move your view port around and select your object from a different angle.
If anyone still have this problem, and having trouble fixing it. I noticed the way I created the problem was by being in Local View and hitting 1, 2 or 3 while in Object mode and not in Edit mode. (Orignally wanting to change between Vertex, Edge and Face Select). Resulting in changing the active Collection.
Apparently doing so while in Local View changes Collection but keeps the Objects currently selected for Local View and therefore leaves them inoperable. To fix it just hit the number in order of the Collection you are currently working with and they will be operable again.
If you have backface culling checked off in the object's Shading menu, you may need to flip the normals.
Change your viewport to the solid rendering mode and see if the object disappears from your viewing angle but is visible from the opposite side.
If this is the case, you'll need to flip the normals in edit mode.
In the outliner if you accidentally type while renaming (without having renaming properly started) you can mess up the selection enabled flags.
Type 'a' to 'select all' (in the outliner) and then 's' to re-enable the selection enabled icons (arrows between eye and camera).