Problems with my edit mode

I have to make an animation intro of my works logo for their demo reel so I modeled the mesh for it. To make things simple say I have two cubes and a sphere. If I highlight either of the cubes and try to go into edit mode with them it sends the sphere into edit mode. If I delete the sphere neither of the cubes will be aloud to get into edit mode. I’ve never encountered this problem before and I feel weird asking for help. I think the problem may be that I have to do this project on my MacbookPro. Please let me know how to fix this, im sure, simple problem.

Using a macbook is irrelevant. Attach you blend to your post or other hosting site.

I’m sorry I can’t. I don’t think my work would allow it.

Sorry can’t help you then