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.
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).