Windows Vista introduced major security and graphics changes, but driver incompatibilities, heavy hardware demands, confusing edition promises, and slow early performance damaged the launch before later service packs stabilized it.
WinFS promised relational metadata and rich queries over Windows data, but the feature was cut from Longhorn, spun into a separate effort, and ultimately dissolved into SQL and data-programming technologies.
Microsoft's Longhorn project accumulated an ambitious new storage system, presentation stack, managed-code experiments, security work, and shell changes until the Windows team reset development onto a stable Windows Server 2003 base.