Nor to my knowledge do I have, or have ever had, let alone had to use, the Apple Update Software on my computer. They appear to work in different ways, and never the twian shall meet! I have to confess, I don't understand what is going though Apple's mind with this. There appears to be two different versions of iTunes the Apple version from Apple, and the Apple version from Microsoft (i.e. (I'm not holding my breath waiting for an answer on the second point.) I would not have joined in this discussion, except that I hate to see your problem unresolved and I'm curious about why there is an issue in the first place. Both should be available from - you may need to scroll down the page a little, click a link for other versions, then scroll up again.

This should be the preferred install for Windows 10, although occasionally I've advised people to try the other version as a workaround. It is normally automatic and you don't have each developer running their own task checking for updates. When using the version from the Microsoft Store updates are managed by Windows in much the same way that apps get updated in Apple's App Store. The other is the version delivered by the Microsoft store which will appear simply as iTunes in your programs control panel/settings and is what you would normally install in Windows 10.

Others include Apple Application Support, Apple Mobile Device Support, Bonjour, etc. One is the old school iTunes(64)Setup.exe installer (in both 32- & 64-bit versions) which comprises several components, one of which is Apple Software Update. As noted there are two primary versions of iTunes for Windows.

Itunes install and update