What happened to Gen. George McClellan after the battle of Antietam? What was Lincoln's reason for this action?

Following his presidential defeat, McClellan resigned from the army and spent several years in Europe. He would return to the railroad business in 1872 as president of the Atlantic and Great Western Railroad.

Explanation:

The Battle of Antietam was the single bloodiest day of combat in the Civil War, and while it was presented as a Union victory in the Northern press, it was in effect a tactical draw. Frustrated that McClellan had again failed to destroy Lee's army, Lincoln officially removed him from command in November 1862.