I need to restore my macbook. Do I simply need to copy the Lightroom folder to an external drive and then move it back when I reinstall Lightroom? Is that all is needed to ensure I don't lose my catalog and presets?
normally data is not affected by a system restore.
however, if you're going to reformat your hard drive and reinstall your os, you will need to back up your data (not just lr) to a partition (external or internal) not affected by the reformat.