Use an Intel iMac as an external display for an Apple Silicon Mac — free, no dongle, via Thunderbolt Bridge.

If TargetBridge is useful to you, a ⭐ on GitHub helps others find it.

Apple dropped Target Display Mode in 2014 with the 5K iMac — and it never came back. TargetBridge brings it back via software, streaming your screen to the iMac at up to 5K over a direct Thunderbolt cable.

Sender (Apple Silicon Mac) — waiting for connection:

Sender — active stream (5K, HEVC):

Receiver (Intel iMac) — waiting for sender:

iMac connected at native resolution via Thunderbolt:

→ Download latest release (pre-built apps, no Xcode needed)

• TargetBridge.app.zip — Sender (Apple Silicon Mac, requires macOS 14 Sonoma or later)
• TargetBridge-Receiver.app.zip — Receiver (Intel iMac, requires macOS 13 Ventura or later)

Unzip and double-click. On first launch, grant Screen Recording permission to the sender.

"App is damaged" warning? macOS quarantines unsigned apps downloaded from the browser. Run this in Terminal, then try again:

xattr -cr ~/Downloads/TargetBridge.app
xattr -cr ~/Downloads/TargetBridge\ Receiver.app

Pre-built receiver crashing? Make sure you downloaded v1.2.0 or later — older builds required Homebrew or macOS 14. Re-download from the latest release.

• Sender: Apple Silicon Mac (M1 or later), macOS 14 Sonoma or later, TB3/4/5
• Receiver: Intel iMac 2017 or later, macOS 13 Ventura or later, TB3/4/5
• Thunderbolt 3/4/5 cable (backwards compatible)

• Standard · 2560 × 1440 — conservative baseline
• Smooth · 2560 × 1440 @ 60 — lower latency motion
• Smooth+ · 3200 × 1800 @ 60 — sharper motion profile
• Crisp · 3840 × 2160 @ 48 — clearer text with HEVC
• 5K · 5120 × 2880 @ 48 — native iMac 5K stream with HEVC

The sender can stream either an extended virtual display or a mirror of the sender display.

For an extended desktop, choose Extended display on the sender before connecting. After the virtual display appears, open macOS System Settings → Displays → Arrange on the sender Mac and position the external display where you want it.

If the receiver does not fill the iMac panel or the cursor/desktop feels scaled incorrectly, select the external TargetBridge display in macOS Display Settings and choose the matching resolution. For the 27-inch 5K iMac path, use a high-clarity stream profile such as Crisp or 5K with the external display set to the matching 2560 × 1440 HiDPI mode.

• TargetBridge-Sender
• TargetBridge-Receiver

• Italian: TargetBridge-QuickStart-IT.md
• English: TargetBridge-QuickStart-EN.md