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It could be that your Mac already recognizes the device, but just isn’t showing its icon on the desktop screen. Mac not formatted to display external drives on the desktop.For more information, go to the same menu option, then select System Report. The best way to look for an incorrectly formatted drive is to go toĪpple (in the top toolbar menu) > About This Mac > Storage. If you’ve got a PC or laptop, it’s worth connecting and seeing if you can access the files through another device.
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It could be that you are trying to connect something only fit to interact with Windows devices. Not every external drive is optimized for Macs. Restarting your Mac essentially clears your macOS’s memory and starts it up fresh. Or press and hold the power button and, when a dialog box appears, click the Restart or press R. Hopefully, some data damage that can be fixed by restarting. Sometimes, if a USB disk won't boot, the cause is macOS issue.
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If you’ve got another port, try connecting the device to that one. It could be a hardware issue with the Mac. Try connecting the same device with a different cable. Assuming it’s plugged in correctly, not wobbly or loose, the cable could be at fault. It sounds obvious, but since this relies on a wire - either a USB cable or HDMI cable - if it’s not connected properly then it won’t appear on your desktop.
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