Cannot keep a drive, any drive, connected on USB C ports - constant disconnections and crashes. This happens on powered hubs, direct connections, both USB C ports do the same and can find no hardware issues, machine passes diagnostics no errors found, drives are APFS and Exfat
iMac Line (2012 and Later)
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Disconnect the hub and the external HDs and troubleshoot as I recommended. it is not uncommon for external peripherals (including USB hubs) to cause issues. If the USB does NOT have it's own power supply that is also and issue, all hubs and docks should have their own power supply and SHOULD NOT be bus powered.
I have 2 HDDs connected. A 500Gb Seagate SD and a 1tb Lacie HDD for time machine. I have tested with multiple other drives and problem exists with them all.;
All other devices are on powered USB hub and include a printer and some lights and thats it. This is exactly the same config as my 21.5 iMac that this one replaced and had no issues on that system
Im doing this- however i will note that my usb hub is an expensive powered one and i have had issues with four drives that work fine on the 3 other macs in the house, the only one i have issues with is the brand new imac. The exact same devices were plugged into my older imac with no issues at all. I do not believe this issue is drive related
You have a LOT of external HD's connected to the computer. I suspect one of them is causing the problem or the dock you are using. Please disconnect all of them then restart in Safe Mode and then add 1 test it for hours (at least 3 hours) and then add another until you find the one that is causing the issue.
New iMac disconnecting drives on USB C constantly
