To resolve common customization issues with the Finder sidebar on your MacBook Pro, you can try closing all Finder windows, then selecting "Show Toolbar" under the "View" menu. This will enable the toolbar and allow you to restore the sidebar. Alternatively, you can try selecting the "Enclosing Folder" option from the "Go" menu, accessing Finder system preferences, or using keyboard shortcuts such as Command + Option + S. If these methods don't work, you can use Terminal commands to remove the Finder preference file and regenerate the sidebar.