* The TC works "best" with "green" drives. Your Seagate Exos X16 is an enterprise-class hard drive, designed for high-performance and reliability in data center environments. The TC may not provide sufficient power to this drive, and maybe why it is acting as it is.
* AFAIK, the TC's firmware can only support up to 3TB drives. However, I am aware that folks have been successful with using much larger drives. Regardless, when placed inside the TC, the TC's firmware will format it into three separate partitions to support its dedicated use for Time Machine.
* Interestingly, some drives are particular on how they are orientated. As you are aware, the drive inside the TC will be in a fixed downward position. Whether or not this Seagate would have an issue with this, I don't know for sure.
* Finally, double-check to see if this drive uses SMR. This is typical of Seagate drives > 4TBs. These are known to be problematic with the TCs.
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... oh, and yes, although this topic seems similar to that of the OP, it's really not, and you should start a new post to make sure it gets the attention it deserves.
Ok, a few things here:
* The TC works "best" with "green" drives. Your Seagate Exos X16 is an enterprise-class hard drive, designed for high-performance and reliability in data center environments. The TC may not provide sufficient power to this drive, and maybe why it is acting as it is.
* AFAIK, the TC's firmware can only support up to 3TB drives. However, I am aware that folks have been successful with using much larger drives. Regardless, when placed inside the TC, the TC's firmware will format it into three separate partitions to support its dedicated use for Time Machine.
* Interestingly, some drives are particular on how they are orientated. As you are aware, the drive inside the TC will be in a fixed downward position. Whether or not this Seagate would have an issue with this, I don't know for sure.
* Finally, double-check to see if this drive uses SMR. This is typical of Seagate drives > 4TBs. These are known to be problematic with the TCs.