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I am trying to get to the bottom of "USB ACCESSORIES DISABLED Unplug the accessory using too much power to re-enable USB devices" notifications I get on my 2014 iMac. These pop ups occur irrespective of: (1) which USB cables I use (2) whether the devices are directly connected to the iMac or through a powered hub (3) whether one ore more devices are connected to the powered hub. The devices in question are Seagate Backup+Hub external drives, which are themselves also self-powered. System Information app shows the devices with no indication of over limit problems (e.g., a drive may show requires 500ma using 100ma). dmesg: [ 838.878907]: 000838.878906 AppleUSB20HubPort@14114300: AppleUSBHostPort::interruptOccurred: overcurrent detected with port status 0x0, localSimulatedInterrupts = 0x1 [ 843.894384]: 000843.894382 AppleUSB30HubPort@14814300: AppleUSBHostPort::interruptOccurred: overcurrent detected with port status 0x4000, localSimulatedInterrupts = 0x1 [ 843.980643]: 000843.980642 AppleUSB20HubPort@14114300: AppleUSBHostPort::interruptOccurred: overcurrent detected with port status 0x0, localSimulatedInterrupts = 0x1 I get absolutely no discernible data errors or corruption on the drives, and the messages seem to have no effect on the volume mounts or filesystem operations. Several Seagate drives exhibit the issue. Seagate blames Apple. So, I've resorted to capturing XHC20 traffic with Wireshark to see if I can figure out the bus messages that cause the warnings. However, I have no idea what to look for as I've never done low level USB work. Any hints? Given the lack of actual problems, I would certainly love to at least be able to squelch the on screen notifications. Any hints?