Q: How to reinstall iclou64.msi on windows 8.1?

Hello there, anastasiaboldt1.

It seems you're having issues reinstalling iCloud for Windows on your Windows 8 computer. The following Knowledge Base article goes into the specifics steps to follow for making sure you've uninstalled iCloud for Windows properly:

Set up and use iCloud for Windows

Turn off or uninstall iCloud for Windows

If you turn off a service in iCloud for Windows, your data won't automatically be kept up to date in iCloud, and you won't see updates made on your other devices. Follow these steps to turn off a service or iCloud:

• To turn off a service on your PC, Open iCloud for Windows, then select or deselect that service. To save your changes, click Apply.
• To turn off iCloud for Windows, open iCloud for Windows, then sign out.

If you want to uninstall iCloud for Windows, remember to make a copy of your iCloud data and save it on your PC. Then sign out of iCloud for Windows on your PC, and follow these steps:Windows 8 or later:

1. Go to the Start screen, right-click in the bottom-left corner or click, then select Control Panel.
2. Click Uninstall a Program.
3. Click iCloud > Uninstall.
4. When asked to confirm, select Yes.

Once you've gone over that, then follow the instructions for reinstalling:

What you'll need

Before you download iCloud for Windows, you'll need an iCloud account. You can sign in to iCloud with your Apple ID. Just follow the set up instructions for your iPhone, iPad, or iPod touch with iOS 5 or later or Mac with OS X Lion v10.7.4 or later.

Depending on what information you want to keep up to date in iCloud, you might need a few other things:

• Mail, Contacts, Calendars, and Reminders: Outlook 2007 through Outlook 2016.
• Bookmarks: Safari 5.1.7 or later, Internet Explorer 10 or later, Firefox 22 or later, or Google Chrome 28 or later.
• Documents: iCloud Drive set up on each of your devices.

Set up iCloud for Windows

You need to download and install iCloud for Windows before you can start using it.

1. Download iCloud for Windows. If it doesn't install automatically, go to File Explorer and open iCloud Setup.
2. Restart your computer.
3. Make sure iCloud for Windows is open. If it doesn't open automatically, go to Start, open Apps or Programs, and open iCloud for Windows.
4. Enter your Apple ID to sign in to iCloud.
5. Choose the features and content that you want to keep up to date across your devices.
   
6. Click Apply.

Thanks for reaching out to Apple Support Communities.

Cheers.