Go to this location
C:\Program Files (x86)\Download Surgeon\
In this folder do you see the following files
ytdl.exe
ytdl.exe.new
If you see only the first, one is that date on this file? Let me know.
If you see both, delete the first, and rename the second one to ytdl.exe by delete
the word "new" at the end. Then retry the OS downloader again.
LEt me know.