LaCie external HDD no longer recognised
My LaCie drive (2TB Rugged Thunderbolt) has been working fine connected via Thunderbolt 2 (the old squarish shaped connector) to my 2015 IMAC 5K. When this broke beyond economic repair, I have just now purchased a new 2020 IMAC 5k and am trying to connect the drive to it via the new Thunderbolt 3 (USB-C) connexions on the IMAC. The drive is not recognised. I tried using a new branded Apple Thunderbolt 3 cable rather than the inbuilt one that comes with the LaCie drive with no success either.
If I connect the drive via the LaCie provided USB cable (USB-C on the LaCie to USB-3 on the IMAC, the drive IS recognised but obviously I want to use the faster Thunderbolt connection.
When the drive is attached via USB-C, the IMAC system report says no devices are connected. I have no other USB-C devices to test with the IMAC.
Is there a compatibility issue at play here or are the USB-C ports on the IMAC faulty?
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