yichen-mac-wechat-dual-open · diff

git:20260713.539b4ec to git:20260713.b3764fd

2 added, 2 removed. Audit A to A.

---

- name: mac-wechat-dual-open

+ name: yichen-mac-wechat-dual-open

description: |

Create, inspect, repair, and polish a second WeChat app on macOS.

Copy WeChat, change the bundle identifier, ad-hoc re-sign, launch the second

instance, set Chinese language preferences, and recolor only the copied app

icon from WeChat green to blue. Use when the user asks whether Mac WeChat

dual-open methods are reliable, asks to double-open WeChat, fix WeChat-2

language/icon/cache issues, or make the second WeChat visually distinct

without installing third-party injection tools.

---

# Mac WeChat Dual Open

Create a second WeChat instance on macOS for running two accounts simultaneously.

## Core Method

The underlying mechanism is simple — macOS distinguishes apps by their bundle

identifier. By copying WeChat, changing the copy's bundle ID, and re-signing

it locally, macOS treats the copy as a separate app that can run alongside the

original:

1. Copy `/Applications/WeChat.app` to `~/Applications/WeChat-2.app`.

2. Change the copy's `CFBundleIdentifier` (e.g., to `com.tencent.xin2`).

3. Re-sign the copy with `codesign --force --deep --sign -`.

4. Launch the copy via its executable directly.

No third-party injection tools or modified binaries required.

## Prerequisites

- macOS 12+ with WeChat installed at `/Applications/WeChat.app`

- Python 3.10+ (system python works)

- Pillow (`pip3 install Pillow`) — required only for `recolor-icon`

- Xcode Command Line Tools (`xcode-select --install`) for `codesign`, `iconutil`, `sips`

## Locating the Script

The helper script lives at `scripts/wechat_dual_open.py` relative to this skill

directory. Different agents install skills to different paths. Construct the

script path dynamically:

```bash

# Auto-detect skill directory

- SKILL_DIR="$(dirname "$(find ~ -path '*/mac-wechat-dual-open/SKILL.md' -maxdepth 4 2>/dev/null | head -1)")"

+ SKILL_DIR="$(dirname "$(find ~ -path '*/yichen-mac-wechat-dual-open/SKILL.md' -maxdepth 4 2>/dev/null | head -1)")"

SCRIPT="$SKILL_DIR/scripts/wechat_dual_open.py"

```

## Quick Commands

```bash

python3 "$SCRIPT" status # Check current state

python3 "$SCRIPT" create # Create the second WeChat

python3 "$SCRIPT" set-language --languages zh-Hans en # Set Chinese

python3 "$SCRIPT" recolor-icon --blue "#1296db" # Blue icon

python3 "$SCRIPT" launch # Start the second instance

python3 "$SCRIPT" repair # Fix bundle id, signing, language, caches

```

Default paths (override with `--source-app`, `--target-app`, `--bundle-id`):

- Source: `/Applications/WeChat.app`

- Target: `~/Applications/WeChat-2.app`

- Bundle ID: `com.tencent.xin2`

## Workflow

1. **Status first.** Run `status` to see what already exists.

2. **Create.** If no second app exists, run `create`. This copies the app,

changes the bundle ID, sets Chinese language, removes `CFBundleIconName`,

re-signs, and registers with Launch Services.

3. **Language.** If the second instance opens in English, run `set-language`,

then restart it.

4. **Icon.** Run `recolor-icon` to change the WeChat green to a user-chosen

blue. The script handles both the outer `AppIcon.icns` and the embedded

`WeChatAppEx.app/.../app.icns`, removes `CFBundleIconName` to avoid stale

`Assets.car` entries, and sets a Finder custom icon when the Carbon-era

tools (`DeRez`, `Rez`, `SetFile`) are available.

5. **Launch.** Run `launch`. The second WeChat should appear with its own login

window. Pin it to the Dock separately from the original.

## Reliability & Tradeoffs

This is **not** an official method. Rate it roughly 6.5–7 / 10 for reliability:

- Works on many macOS + WeChat version combinations.

- No code injection or third-party tweaks — easy to inspect and undo.

- **Breaks after WeChat updates.** Re-run `create` (or `repair`) after

updating the original WeChat.

- Push notifications may be unreliable (APNs tied to original identity).

- Login state and Keychain are isolated per bundle ID.

- Ad-hoc signing may fail if WeChat adds stricter signature checks.

See `references/reliability-and-risks.md` for the full analysis.

## Icon Pitfalls

WeChat stores icons in multiple locations. The script handles all of them:

| Location | What it affects |

|----------|----------------|

| `Contents/Resources/AppIcon.icns` | Main app icon |

| `Contents/MacOS/WeChatAppEx.app/Contents/Resources/app.icns` | Embedded runtime icon |

| `Contents/Resources/Assets.car` | Asset catalog (handled via `CFBundleIconName` removal) |

| `Icon\r` + Finder custom icon attr | Finder "Applications" view |

If the user reports the icon is still green:

- They may be looking at `/Applications/WeChat.app` (the original), not

`~/Applications/WeChat-2.app`. Verify with `open -R ~/Applications/WeChat-2.app`.

- Dock caches per-process icons. Quit and relaunch WeChat-2.

- The Finder custom icon step requires `DeRez`/`Rez`/`SetFile` which may not

exist on macOS 13+. The script skips gracefully — icns replacement is usually

sufficient.

## Safety

- **Never modify `/Applications/WeChat.app`** — all changes are scoped to the copy.

- Ask before deleting an existing second app. Prefer `repair` over delete/recreate.

- The `codesign` step must run **before** adding a Finder custom icon, otherwise

macOS rejects the bundle with "resource fork, Finder information, or similar

detritus not allowed".

## References & Attribution

- Original tutorial by [@koffuxu](https://x.com/koffuxu/status/2043110831584690427)

(2026-04, blog post: "Mac 微信双开最完美方案")

- Confirmed by [@MinLiBuilds](https://x.com/MinLiBuilds/status/2043121624971678083)

(2026-04)

- Icon recoloring uses HSV/HLS hue rotation via Pillow.

- Finder custom icon technique uses classic Carbon resource tools (`DeRez`/`Rez`).