If I disable iCloud Sync in MN3 settings, specifically ‘Cloud > from iCloud to None,’ do I risk losing any data? How can I determine if the notebooks currently on my iPad are stored locally or in the cloud?
If you see them on the iPad and are able to open them, then they are on your iPad 
it’s not possible to open a notebook without first downloading it to the local device.
Hello
If there is no setting, there is no risk.
Kind Regards,
Support Team
Disabling iCloud Backup does not inherently risk data loss. However, it means your device won’t back up its data to iCloud automatically. It’s crucial to regularly back up your device through other means like iTunes or manually back up to iCloud to avoid potential data loss due to device damage or loss. While turning off iCloud Backup won’t delete existing data, failure to maintain alternative backups could result in data loss if something happens to your device.
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Delhi Training Courses