Added new device to Family Classic account - one drive deleted first device documents

A Microsoft 365 Family subscription and OneDrive are designed to sync data per account, not per device. What happened is most likely due to account mix‑ups and OneDrive folder backup/sync behavior, not Windows 10 vs. 11 or the age of the laptop.

Key points about how this works and why files “moved” or were deleted:

1. One Microsoft account = one OneDrive
   • Each Microsoft account has its own OneDrive. If both laptops are signed into the same Microsoft account for OneDrive, they will share the same OneDrive storage and sync the same Desktop, Documents, and Pictures folders (if backup is enabled).
   • If the new laptop was set up using the same Microsoft account that owns the Family subscription, OneDrive on that device will sync the same folders and can move/delete files in a way that affects both devices.
2. Folder backup can relocate Desktop/Documents/Pictures
   • When OneDrive “backs up” folders, it can move Desktop, Documents, and Pictures into the OneDrive folder. Deleting or changing those folders on one device can affect the same folders on the other device because they are actually the same OneDrive locations.
   • This is why files disappeared from the Documents and Pictures folders on the older laptop and then appeared in the OneDrive recycle bin.
3. Files deleted via OneDrive go to the OneDrive recycle bin
   • When files are deleted from a OneDrive‑synced folder, they typically go to the OneDrive recycle bin, which is why they were recoverable there.
   • If files are deleted from the local OneDrive folder in a way that bypasses the recycle bin (for example, deleting the OneDrive folder itself), recovery options are limited and may require third‑party tools, and success is not guaranteed.
4. Multiple accounts and devices can cause confusion
   • If there are multiple Microsoft accounts in the household, it is easy to sign into the wrong one on a new device. That can make it look like “everything changed to his info” because the device is now using his account profile and OneDrive.
   • The recently used file lists in Office apps also sync with the Microsoft account, so unexpected files can appear if someone else uses the same account on another device.
5. What to do going forward
   • Ensure each person has their own Microsoft account and OneDrive, and that each device is signed into the intended account.
   • On each PC, open the OneDrive settings (cloud icon in the notification area → Settings → Account → Choose folders / Manage backup) and confirm which folders are being backed up to OneDrive. Disable backup for folders that should remain strictly local.
   • For files that must never be deleted or moved by sync, store them in a non‑OneDrive folder (for example, a local folder that is not under OneDrive\Desktop, OneDrive\Documents, or OneDrive\Pictures).

If files are missing again, check:

• The OneDrive website for that account and search for the files.
• The OneDrive recycle bin and restore items if present.
• Whether the correct Microsoft account is being used on each device.

References:

• My OneDrive says it's full
• Sync files with OneDrive in Windows
• Use OneDrive on Windows 10 devices (Xbox, HoloLens, Surface Hub, or tablets)
• Find lost or missing files in OneDrive
• Unable to restore deleted files from C:OneDrive - Microsoft Q&A
• onedrive sync? - Microsoft Q&A
• Customize the list of recently used files in Office apps