Microsoft 365’s click-to-run installer famously chokes on stock Wine. This flake sidesteps that by running it through GE-Proton, the Wine build Valve and GloriousEggroll ship to make Windows games work on Steam Deck — one nix run .#ms365 -- install fetches the real Office Deployment Tool and installs Word, Excel, and the rest into a dedicated prefix. It downloads several gigabytes and needs a genuine Microsoft 365 license to sign into; the payoff is Office running with no virtual machine anywhere.