Help

• The iPad is not in Screen MirroringAlmost every case is one of four things: the two devices are on different Apple Accounts, Bluetooth is off on one of them, the iPad has not been unlocked since it last restarted, or one device is sharing its internet connection.
• Sidecar says the device is locked or asleepThe Mac reached your iPad and the iPad refused because its screen is locked or off.
• Screen Sharing is blank on a Mac with no monitormacOS only renders a desktop when a display exists.
• Opening SideMini, which is not on the App StoreSideMini is signed with an Apple Developer ID and notarized by Apple, so it opens normally: double-click and it launches.
• Activating your licenceClick the SideMini icon in the menu bar, choose Enter License, paste the key from your purchase email and press Activate.
• Uninstalling SideMiniUndo the system settings from inside the app first, then quit it and drag it to the Trash.

Guides, not fixes

Longer background reading lives on the blog: how Sidecar works, what a headless Mac does at boot, and how the alternatives compare.