Fix Claude Desktop 0x80070020: Won't Launch After Update
Right after you update Claude Desktop (Windows), launching the app pops "Another program is currently using this file" and it won't start — and it stays broken until you restart the PC. This is a known bug in the Microsoft Store (MSIX) build (GitHub #53247 and others). The key point: a full PC restart is not necessarily needed — in many cases just signing out of Windows and back in recovers it (not a PC restart, and not logging out of Claude), because the orphaned handle behind it persists per Windows user session. Stopping CoworkVMService or re-registering the package is reported NOT to work. Despite the dialog wording, it is verified there is no user-space file lock (handle.exe / Process Explorer): the real failure is in the AppX/Desktop Bridge container layer, at the Job Object → Silo conversion (0x80070020 = ERROR_SHARING_VIOLATION, events 215/208). The trigger has two unsettled explanations — the service holding the Job Object (#57221) vs. a startup crash leaving cleanup undone (#53247) — and no official fix has shipped. The permanent workaround is switching to the Squirrel (installer) build. Based on one machine (Windows 11 Home 10.0.26200) cross-checked with GitHub issues; confidence-labeled throughout.