Problem

Unable to log in to iCloud on Windows 11, a blank dialog box pops up.

Unable to log in to iCloud on Windows 11, with the error message iCloud for Windows has not been initialized, please try logging in later.

Solution

Delete Certificates

Press Win+R, type certmgr.msc, select Personal, then Certificates, find the certificate(s) issued by Apple iPhone Device CA, and delete it (if there are multiple, it is recommended to delete all of them).

Delete Files

Run the following script in a PowerShell terminal:

Get-ChildItem -Path "$env:APPDATA\Microsoft\Crypto\" -File -Recurse | ForEach-Object { if (Get-Content $_.FullName | Select-String -Pattern "APNSDaemon") { $_ } } | Format-Table -Wrap

Then open File Explorer, navigate to %APPDATA%\Microsoft\Crypto\RSA. There should be a folder with a name similar to S-1-5-21.... Back it up and then enter this folder.

Delete the files output by the script.

Restart the Computer

Additional Notes

If the issue is not resolved after restarting, uninstall iCloud, repeat the steps above, then reinstall iCloud and try logging in again.