When Windows users suddenly discover that their files have vanished from their desktops after interacting with OneDrive, the issue often stems from how Microsoft’s cloud service integrates with the operating system. The automatic, near-invisible shift to cloud-based storage has triggered strong reactions from users who find the feature unintuitive and, in some cases, destructive to their local files.
No the issue is once enabled your home directory becomes onedrive. People feel they are saving files into their users/myuser/Documents but they’re actually saving it to users/myuser/Onedrive/Documents. These files are being synced off into the cloud and only pulled down when requested. Then the user decides they dont want onedrive and so they turn it off by unlinking their account. Now they feel they’ve lost their files but they havent the files are still in one drive and they need to go get them after that they have local files as normal.
Its purely user error encouraged by microsofts pushy implementation and bad design.
It is this, coupled with so many people not even knowing that they are using OneDrive (because it was automatically enabled if you have a Microsoft account linked to your Windows install, and Microsoft pushing to link your account).