For those who don't want to lose the ability to restore old apps, etc, here are the direct download links:
iTunes 12.6.2.20 for Macintosh (64-bit):
https://secure-appldnld.apple.com/i...-762D-11E7-9558-75E7484DD6D5/iTunes12.6.2.dmg
iTunes 12.6.2.20 for Windows (32-bit):
https://secure-appldnld.apple.com/i...C-6BB9-11E7-A52A-C7374A4DD6D5/iTunesSetup.exe
iTunes 12.6.2.20 for Windows (64-bit):
https://secure-appldnld.apple.com/i...6BB9-11E7-A878-C6374A4DD6D5/iTunes64Setup.exe
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I'm on a Mac. It was telling me that there is already a current version, when I hit ok...the installation window closed.