The latest update from Microsoft has an (Optional) Hardware Update - the "Via Storage - Primary IDE Controller" - that will cause the OptiPlex to "Blue Screen" on restart, requiring the user to choose "Last known good configuration" when re-booting.
DO NOT INSTALL THIS DOWNLOAD if you have the Dell OptiPlex.
How to discover the Dell model: when starting up there will be a "Dell" startup screen with a progress bar located bottom-middle...the model can be found just above the progress bar.