I use Sidecar with a 2019 16" MBP (Monterey 12.1) and an 12.9" iPad Pro (iPadOS 15.2). The connection is over USB with an Apple USB-C Lightning cable. When I unplug the iPad, all networking connectivity on the Mac is lost. This happens 100% of the time.

The iPad will display "Lost Connection. The session will resume automatically when the connection improves." There's a button to "Disconnect". The disconnect button doesn't do anything and reconnecting the cable doesn't resume the connection.

At this point, the iPad will no longer reconnect with Sidecar. Mac apps with network connectivity begin to hang. The spinning beachball starts to take over. I've tried shutting down the network adapter in Terminal using sudo ifconfig en0 down but then Terminal hangs. The Mac requires a hard reset.

I've looked in the logs but I haven't been able to identify anything that could be related. I also don't know what the Sidecar system is called to refine my search for log entries.

Any suggestions on how to troubleshoot this issue? Has anyone else encountered a similar problem?

  • Sounds like a mechanical/electrical problem. If the connection glitches when you merely bump the cable, then its is either a damaged cable, or damage to any or all of the ports on the MPB & iPad. Your next step is to get a known good (new, perhaps?) interconnect cable and give it a test. In years of experience, cables have proven many times to be the weakest link. They can be damaged internally without any visible external cause. Find some videos on how to (gently) clean the USBC and Lightning ports. Perhaps there's some cruft in them.
    – IconDaemon
    Dec 25, 2021 at 3:07
  • Thanks for the comment. I updated the post to note that simply unplugging the iPad causes the behavior 100% of the time. Even if the cable is bad or there's a mechanical/electrical problem, the OS shouldn't shrug off the lost connection and not take down the entire machine. Any thoughts on what I should search for in the logs? Thanks again.
    – Anthony
    Dec 25, 2021 at 16:57

2 Answers 2


Having the same issue with MBP 2021 14" (Monterey 12.1) and iPad Pro 2019 11" (iOS 14.4.2)

As soon as I disconnect the cable the network connection of MBP breaks down and the only thing to fix this is a restart. When using sidecar via Wifi it works without a hazzle.

  • Is there a way to connect via wifi but leave the cable attached for charging? I've noticed that when the network dies, the Network preferences pane is wiped of all connections. bit.ly/3IUg7cr
    – Anthony
    Jan 31, 2022 at 2:02

Little Snitch is the cause.

I've been through hell and back trying to solve this, but for some reason, Little Snitch interferes with a wired Sidecar connection.

I completely removed Little Snitch from my system and Sidecar behaves as intended. If I unplug the cable, Sidecar reconnects via Wi-Fi/Bluetooth after a few seconds as if nothing happened.

Grrrrr, Little Snitch.

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