iCloud64.msi missing and cannot open iCloud

Hello Peej99.

Thanks for reaching out to Apple Support Communities. If I'm understanding correctly, you are unable to open the iCloud for Windows app because of an error of "iCloud64.msi file" missing and would like to what can be done to resolve this. I will be glad to assist. Uninstalling and reinstalling is what I would recommend to fix this. See below from:Set up and use iCloud for Windows

"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.

Windows 7:

1. Choose Start menu > Control Panel.
2. Click Programs > Program and Features.
3. Select iCloud > Uninstall.
4. Click OK to continue."

Cheers.

Hi Peej99.

Thanks for following up with the additional information. I would suggest contacting Apple Support next:

Contact Apple for support and service

Take care.