Windows desktop app: recurring full UI hang (same WER fault bucket) across v1.22-v1.24

Environment: Windows 11 Home (build 10.0.26200), Claude desktop app x64, MSIX package Claude_pzs8sxrjxfjjc. Heavy Claude Code Desktop use (local sessions, MCP servers, long-running sessions active at hang time).

Symptom: App UI freezes completely - Windows logs MoAppHang / Event 1002 "claude.exe stopped interacting with Windows and was closed." Requires force-quit. Survives app updates and a full reinstall.

Occurrences (local time, EDT):

• Jul 21 17:36 - v1.22209.3
• Jul 24 13:31 - v1.24012.1
• Jul 28 12:15 and 12:21 - v1.24012.9 (double hang; prompted user to reinstall)
• Jul 29 12:39 - v1.24012.9, fresh install from claude.ai - hung during app quit

Signature: WER fault bucket 1576750707325987198, type 5, MoAppHang; report signature Critical_Claude_1.24012.9_53be7de58a127fcb527bcfadc73074224ddc57ca_3c62862e. The three v1.24012.9 hangs share the identical bucket - one deterministic freeze.

Ruled out: no display-driver resets (Event 141/4101), no kernel faults correlated.

Impact: the reinstall wiped the local session index and app scheduled tasks (user recovered manually from ~/.claude transcripts).