[Bug] Claude Desktop main window vanishes silently and stealth update fails to relaunch app

Bug Description
Claude Desktop (Windows, MSIX / Microsoft Store): main window disappears silently and the stealth update quits the app without relaunching ENVIRONMENT - Windows 11 Pro 10.0.26200, desktop PC (DESKTOP-JJMM), 64 GB RAM - Claude Desktop MSIX from Microsoft Store: 1.46388.3 -> 1.46388.4 -> 1.49585.0 - Claude Code (CCD) 2.1.260 running inside the desktop app, several sessions open (heavy use: 80-260 child processes, 5-12 GB tree RSS) - Logs: %LOCALAPPDATA%\Claude\Logs\main.log BUG 1 - Main window vanishes while electron_main and the renderer stay alive; relaunch from the icon does nothing - 2026-09-08 between 13:03 and 13:52 the main window disappeared. main.log has NO entry for it: no window close/hide, no error, no renderer crash. process-memory samples show electron_main (pid 26680) and electron_renderer (pid 16420) alive and stable the whole time. - Clicking the app icon at 13:52:07, 13:52:12 and 13:53:39 logged only: second-instance: suppressing duplicate argv Starting app { Not main instance, returning early from app ready and the primary instance never re-showed its window. The user sees claude.exe in Task Manager but no window. Killing ONE claude.exe does not help (the tree has ~13 processes); only killing the whole tree (taskkill /F /IM claude.exe /T) or rebooting recovers. - Expected: the primary instance should show/focus its window on the second-instance event (or the second instance should take over if the primary has no visible window). BUG 2 - Stealth update quits the app and never relaunches it (reproduced twice) - 2026-09-04 23:10:00 and 2026-09-08 14:12:01, identical sequence: [stealth-update] Triggering stealth update after idle timeout [stealth-relaunch] Saved z-order anchor ... / Saved navigation history [CCD] Killing 8 PTY process tree(s) on quit beforeQuitForUpdate handler fired, going down for update Windows session ending (close-app) - quitting the app After that there is no "Starting app" until the user reboots the machine (04/09: next start 05/09 13:35 after reboot; 08/09: next start 14:41 after reboot at 14:28). The MSIX package WAS updated (Get-AppxPackage shows the new version) but the app did not come back. - On 08/09 the stealth update fired on an instance that was already in the "no window" state of BUG 1, so the user had no idea an update was happening. - Expected: after the MSIX update the app relaunches (stealth-relaunch) or at least leaves a visible window / notification. OTHER OBSERVATIONS - Application event log: "CoworkVMService id 1 [Warning] Claude VM Service: failed to configure SCM recovery actions; if the service crashes it will not restart until the machine reboots: open service: Access is denied." Logged many times per day (15 times on 2026-09-08 14:xx). - Earlier incidents on this machine (03-05/09) were unrelated (DNS outage on the PC), but the same "quit for update and never came back" pattern was already present on 04/09 23:10. LOG EXCERPTS (main.log, 2026-09-08) 12:42:00 [updater] Found an update, downloading 12:42:46 [updater] Update downloaded and ready to install { releaseName: 'Claude 1.49585.0' } 13:03:44 [warn] [claude-in-chrome] Tool call error: browser_batch (1782c8e1) after 4075ms <- last "normal" activity 13:52:07 second-instance: suppressing duplicate argv 13:52:07 Starting app { 13:52:07 Not main instance, returning early from app ready 13:52:12 (same three lines) 13:53:39 (same three lines) 14:12:01 [stealth-update] Triggering stealth update after idle timeout 14:12:01 [stealth-relaunch] Saved z-order anchor: 0x40266 (above our 0xb03f0) 14:12:01 [stealth-relaunch] Saved navigation history (34 entries, active=33) 14:12:02 beforeQuitForUpdate handler fired, going down for update 14:12:02 Windows session ending (close-app) - quitting the app (no further lines until 14:41:59 "Starting app" after a manual reboot) 14:41:59 [updater] Version changed since last launch: 1.46388.4 -> 1.49585.0

Environment Info

• Platform: win32
• Terminal: null
• Version: 2.1.259
• Feedback ID: 942246bd-7a1a-42b8-990a-8fc40858e3f4

Errors

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