Workspace Preferences dialog box has a useful check box, Prompt to Save. You can use this option to set preference for when to get the save workspace message.
By default this is checked and saves changes in the workspace automatically. There is also an option of choosing to save a workspace only when it is open.
For more information please read the article The following link is no longer available. To access this information, copy the title found in the url into the search tool on the top nav bar, or try searching for key words in the post. https://li360.pitneybowes.com/s/article/ka180000000DAd2AAG/64-bit-Workspace-Improvements-in-MapInfo-Pro