Castpane
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Castpane Link, the free Mac helper

Castpane Link is a small, free menu bar app for Mac. You only need it if your Mac does not show your PC in Screen Mirroring while Castpane is running on the PC. For an overview, see the Castpane Link page.

What it does

A Mac only lists receivers that announce themselves on the network. Some Wi-Fi networks, especially office and school ones, pass that traffic in one direction only, so the PC's announcements never reach the Mac.

Castpane Link asks the Castpane PC to send its announcements directly to this Mac. Your PC then appears in the normal Screen Mirroring list in Control Center and you connect as usual. Castpane Link does not carry the mirrored video or sound; that still goes straight from macOS to the PC.

How Castpane Link helps a Mac find the PC The network drops group announcements from the PC to the Mac. Castpane Link on the Mac asks the PC to announce itself directly, and the PC appears in Screen Mirroring. Windows PC Mac with Castpane Link Group announcement lost 1. "Announce to me" 2. Direct announcement
Illustration of how Castpane Link works.

How it finds your PC

  1. If your Mac can already see the PC, Castpane Link has nothing to do.
  2. Otherwise it looks for Castpane PCs on your local network.
  3. If it still finds nothing, type the IP address shown in the Castpane app on your PC.

Castpane Link keeps renewing its request while it is running. When you quit it, the PC stops announcing to your Mac, and after a short while the PC disappears from your Mac's list again unless the network lets the normal announcements through.

Install

Requires
macOS 13 Ventura or later
Build
Universal (Apple silicon and Intel)
Price
Free

Castpane Link is offered on the Mac App Store and as a disk image notarized by Apple. Use whichever you prefer.

From the Mac App Store

  1. Open the Castpane Link page in the Mac App Store and click Get.
  2. Open Castpane Link from your Applications folder. Its icon appears in the menu bar.

From the disk image

  1. Download the disk image.
  2. Open it and drag Castpane Link to your Applications folder.
  3. Open Castpane Link from Applications. Its icon appears in the menu bar.
Castpane Link download coming at launch

First run: allow Local Network access

On macOS 15 Sequoia and later, macOS asks whether Castpane Link may find and connect to devices on your local network. Click Allow. Without this permission it cannot reach your PC.

If you clicked Don't Allow by mistake: open System Settings, then Privacy & Security, then Local Network, and turn on Castpane Link.

Privacy

  • Castpane Link talks only to the Castpane PC on your local network. It only contacts private local addresses.
  • It does not connect to the internet, has no analytics and no account.
  • The only things it sends to your PC are the request to be announced to and, optionally, your Mac's name so the PC can show who asked.

Full details are in the privacy policy.

Uninstall

Quit Castpane Link from its menu bar icon, then move it from Applications to the Trash.

Last updated October 12, 2026. Still stuck? Contact support.

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