There are a number of possible reasons why your scanner may not be appearing in Device Manager.
First, check that the scanner is correctly connected and turned on. Make sure all USB cables are securely connected and that power cords are properly plugged in to an outlet. If your scanner connects through an ethernet cable, make sure it’s in the right port on your router or switch. Also, ensure that the scanner’s power button is set to “On”, and that any applicable toggle switches are in their correct positions.
If you’ve confirmed that the scanner is powered on and connected, try restarting your computer. Shut down your computer, then turn off the scanner and disconnect it. After waiting a few moments, reconnect the scanner and power it back on. Then, turn the computer on and see if the scanner appears in Device Manager. If it still does not, check for any pending Windows updates, as a recent software update may be causing compatibility issues with the scanner.
If the scanner still isn’t appearing in Device Manager, it may be missing required drivers. Visit the manufacturer’s website and download the latest drivers for your scanner model. Run the driver installation program, then restart your computer and check Device Manager again.
It’s possible that the scanner is not compatible with your operating system. If your computer is running an older version of Windows, you may need to upgrade your system to a version that supports your scanner model.
Finally, if you still can’t find your scanner in Device Manager, it’s possible that the hardware has malfunctioned due to age, improper use, or damage. Visit your local electronics repair shop to have a technician inspect the device.