updating iTunes to 12.9.4 on Windows PC

As highlighted for your attention, links are at the bottom of the troubleshooting page. I'll post the current set for you here:

• iTunes 12.9.4.102 for Windows (32-bit) - iTunesSetup.exe (2019-03-25)
• iTunes 12.9.4.102 for Windows (64-bit) - iTunes64Setup.exe (2019-03-25)

tt2

Update to the latest version of iTunes - Apple Support

For general advice see Troubleshooting issues with iTunes for Windows updates.

The steps in the second box are a guide to removing everything related to iTunes and then rebuilding it which is often a good starting point unless the symptoms indicate a more specific approach. When reinstalling right click on the downloaded setup file and use run as administrator. It may also help to temporarily disable any non-Microsoft anti-virus.

Review the other boxes and the list of support documents further down the page in case one of them applies.

The further information area has direct links to the current and recent builds in case you have problems downloading, or want to revert to an older version if the current one won't work properly for you at the moment. Links to the most recent builds are now at the bottom of the page.

Your library and device backups should be unaffected by these steps but there are links to backup and recovery advice should it be needed.

tt2

Click on the link I posted above. After the page appears click on the large box inside which you will see large letters the say, PC.

This one: Update to the latest version of iTunes - Apple Support. But you've been there already. The download is an executable to install iTunes. It will not affect your library.