Try resetting the workspace, and deleting the InDesign SavedData file.
Is the workspace reset by saving a New Workspace under Window/Workspace?
I did go into the Wordspaces preferences folder and deleted the last saved workspace file: (name)_CurrentWorkspace.xml. Those are the InDesign Saved Data files, right?
Doing these two things, I still get the recovery message, so I must be misunderstanding how to do this.
Deleting the currrent workspace xml should reset it, but using the menu (Window > Workspace > Reset [workspace name]) is easier.
For the InDesign SavedData file, which is where the recently opened files list is stored, see Replace Your Preferences
Thank you for that post, it clarifies a lot. It's great to be able to reset the ID SavedData files and not the default preferences, because my problem has now gone away and I didn't have to spend time re-customizing the application.
Thank You Peter! As always, you've been a great help!