There are times when you need to undo a mistake you’ve made in Photoshop. For example, if you accidentally erased a part of your image, you may want to try and re-create it using Photoshop’sundo feature. However, there are also times when you may not want to undo a mistake. For example, if you’re trying to fix a mistake that was made in an earlier version of Photoshop, then undoing the mistake might not be the best idea.