USB ports aren't getting enough power. USB mice aren't power hungry enough for that, but some USB keyboards are hungry. Unfortunately, this includes clickable M models; Results range from a keyboard that won't initialize at all, to looping when trying to initialize and failing halfway, to borderline running and crashing when actively moving the mouse. Plugging a powered USB hub between the USB port on the KVM and the keyboard gets the damn thing working, but it would be much more convenient if the KVM itself had an additional external power supply.
TESmart 1080P 60Hz USB VGA KVM Extender Over Cat5e Cat6 Ethernet Cable - Long Range 984ft/300m (Sender+Receiver)
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🔌 HDMI 2.0 4 Port KVM Switch with 4K@60Hz, 2K@144Hz,1080P@120Hz Support, 18Gbps Bandwidth, USB 2.0 Keyboard/Mouse/Printer/Monitor/PC Selector, Audio Out/Mic In, HDR10, Dolby Vision, Dolby/DTS, HDCP2.2 Compatibility
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Fractal Design Define R5 - ATX Mid Tower Computer Case - High Airflow and Silent Optimized - Includes 2x Dynamix GP-14 140mm Silent Fans - Water-Cooling Ready - Black
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Computer case be quiet! Pure Base 500 black
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Computer case Deepcool Matrexx 55 black
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