[BUG] Japanese VM process name shows as mojibake in Activity Monitor (UTF-8 decoded as Shift-JIS) — still in 1.20186.1

Summary

Still reproducible as of Claude desktop app 1.20186.1 (2026-07-12): when the app UI language is Japanese, the Cowork/sandbox VM helper process gets the localized display name 「Claudeの仮想マシンサービス」, but macOS Activity Monitor shows it as mojibake:

Claude縺ｮ莉ｮ諠ｳ繝槭す繝ｳ繧ｵ繝ｼ繝薙せ

Previously reported in #24398, #24641, #32413 — all were closed as duplicates of each other without a fix, and are now locked, so filing a new issue as instructed by the lock notice.

Environment

• Claude desktop app 1.20186.1, UI language: Japanese
• macOS 26.5.2 (Darwin 25.5.0), Apple Silicon
• Process: /System/Library/Frameworks/Virtualization.framework/Versions/A/XPCServices/com.apple.Virtualization.VirtualMachine.xpc/Contents/MacOS/com.apple.Virtualization.VirtualMachine (Cowork sandbox VM)

Root cause analysis

The garbled string is exactly the UTF-8 bytes of the correct name decoded as Shift-JIS:

>>> "Claudeの仮想マシンサービス".encode("utf-8").decode("shift_jis", errors="replace")
'Claude縺ｮ莉ｮ諠ｳ繝槭す繝ｳ繧ｵ繝ｼ繝薙せ'

The app's localization resources (Contents/Resources/ja-JP.json etc.) contain valid UTF-8, so the string itself is fine. The failure is in the display path: the BSD process (group) name is stored as a raw byte array with no encoding information, and Activity Monitor decodes it with the legacy Japanese system encoding (Shift-JIS/MacJapanese) instead of UTF-8.

Suggested fix

Use an ASCII-only name for the VM helper process (e.g. Claude VM Service) regardless of UI language. Since BSD proc names cannot carry encoding information, any non-ASCII localized name will render as mojibake in Activity Monitor on Japanese (and likely other CJK) systems.

Impact

Cosmetic only — the VM works fine. But a garbled process name looks alarming: users may mistake it for malware.