Problem
Unable to log in to iCloud on Windows 11, a blank pop-up box appears.
Unable to log in to iCloud on Windows 11, showing the message Windows iCloud has not been initialized yet, please log in later.
Solution
Delete Certificate
Press Win+R and enter certmgr.msc, select Personal, Certificates, find the certificate issued by Apple iPhone Device CA, and delete it (if there are multiple, it is recommended to delete all).
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 like S-1-5-21.... After backing up, enter this folder.
Delete the files output by the script.
Restart the Computer
More
If the issue is not resolved after restarting, uninstall iCloud and repeat the above steps, then reinstall iCloud and try logging in.