Claude Desktop writes malformed registry Run entry (nested escaped quotes) - crashes Windows Task Manager and other Run-key parsers

Summary

The Claude Desktop installer writes a malformed value to
HKCU\Software\Microsoft\Windows\CurrentVersion\Run\Claude containing outer
quotes wrapping inner escaped quotes. This shape is not parseable by
PathGetArgs() / PathUnquoteSpaces() in shlwapi, which return NULL and
cause downstream apps that dereference the result to crash with an access
violation. The most visible casualty is Windows Task Manager, which crashes
silently when the user clicks "More details" and the Startup tab enumerates Run
entries.

Repro

1. Install Claude Desktop on Windows 10 22H2 (and likely Win11 — same shlwapi parsing code).
2. Open regedit → HKCU\Software\Microsoft\Windows\CurrentVersion\Run.
3. Inspect the Claude value. On affected installs it appears as (raw characters, 71 bytes):

``
"\"C:\Users\<user>\AppData\Local\AnthropicClaude\claude.exe\" --startup"
`
Note: outer " wrapping an inner \"…\"` escape pair.

1. Open Task Manager (Ctrl+Shift+Esc). Click More details.
2. Task Manager exits silently with no error dialog and no Application Error event surfacing meaningful info to the user.

Expected

The Run value should follow the canonical Windows shell convention: a single
pair of outer quotes around the executable path only, with arguments outside the
quotes. Bytes 67:

"C:\Users\<user>\AppData\Local\AnthropicClaude\claude.exe" --startup

Replacing the malformed value with the canonical form immediately stops Task
Manager from crashing (verified on the reporter's machine, 2026-05-28).

Crash signature

Windows Application Error event (event ID 1000), reproducible deterministically:

Faulting application name: taskmgr.exe, version: 10.0.19041.6280
Faulting module name:      taskmgr.exe, version: 10.0.19041.6280
Exception code: 0xc0000005       (access violation)
Fault offset:   0x00000000000748a1   (deterministic, identical across 15+ crashes)
Faulting application path: C:\Windows\system32\taskmgr.exe

Crash dumps in %LOCALAPPDATA%\CrashDumps\Taskmgr.exe.*.dmp (~2.5 MB each).

Impact

This is not a Task Manager regression — Task Manager is the messenger. The bug
ships in Claude Desktop's installer. Any application that enumerates Run entries
using the standard shlwapi quote-parsing helpers is at risk; Task Manager is
the highest-visibility example because every Windows user opens it. Public
reports of this exact symptom appeared in April–May 2026 in r/Windows10,
r/Windows10TechSupport, and Microsoft Q&A, with users (and forum responders)
gradually attributing the crash to a Claude Desktop install. Multiple users
attempted the entire system-repair toolkit (sfc /scannow, DISM RestoreHealth,
lodctr /R perfmon counter rebuild, GPU driver updates) before identifying the
real cause via the registry.

Affected versions

The reporter's machine had Claude Desktop installed at the path
C:\Users\<user>\AppData\Local\AnthropicClaude\claude.exe. Public reports
identify at least Claude Desktop 1.5354.0 as a confirmed source; another
report references 1.8555.2.0. The bug appears to be present from at least
those builds forward.

Environment

• Windows 10 Pro for Workstations 22H2, build 19045.6466
• Hardware: Lenovo ThinkPad T15g Gen 2 (Intel Xeon W-11855M + NVIDIA RTX 3080 Laptop, hybrid Optimus)
• WSL 2.7.3.0, Docker Desktop 4.75.0 (irrelevant but installed)
• Other apps that write to HKCU Run (OneDrive, Teams, Steam, Edge, Perplexity Comet, NVIDIA Broadcast, OpenVPN, Citrix, Cisco WebEx) write proper values with a single quote pair — Claude Desktop is the sole entry with nested-escape form.

Suggested fix

The installer should use the standard lpCommandLine formation:

swprintf(cmdLine, MAX_PATH+32, L"\"%ls\" --startup", exePath);

(or whichever toolkit is appropriate for the installer language) — producing
the canonical single-quoted form.

If retroactive cleanup of already-deployed installs is in scope, the next
Claude Desktop update could detect a malformed Claude value on launch and
silently rewrite it to the canonical form. Pattern detection: leading
characters "\" are sufficient to flag the malformed shape.

References

• Public discussion thread describing identical symptom and the PathGetArgs() / PathUnquoteSpaces() NULL-deref attribution: https://www.reddit.com/r/Windows10TechSupport/comments/1spoo0l/task_manager_crashes_when_expanded_compact_mode/
• Related r/Windows10 thread naming Claude Desktop as the source: https://www.reddit.com/r/Windows10/comments/1sliyet/claude_desktop_install_breaks_windows_task/

Reporter mitigation

Wrote the canonical form back to the registry; Task Manager stopped crashing
immediately. Backup of original malformed value preserved at
%USERPROFILE%\claude-run-key-backup-2026-05-28.reg.