16TB external SSD not able to format to AFPS in Disk Utility on MacBook Air

It would help if you provide the exact make & model of the SSD.

The error message would seem to indicate a problem with the SSD.

But you could try an alternate path ... in Disk Utility, select the Device, then Partition and make sure you have a GUID partition. Then format it as MacOS Extended Journaled (GUID partition map). If that is successful, then either convert the SSD to APFS (using Disk Utility) or reformat it as APFS.

Even so, I would be suspicious of the SSD and consider returning it for credit or exchange.

The number of responders here that have that specific brand and capacity 16 TB SSD probably approaches zero, so how could anyone determine another course of action other than exchange the drive for a replacement and try to format it as APFS again.

Did you select the drive identity entry in the Disk Utility side bar?

Apple does not ship 16 TB SSD and may not have tested Disk Utility against a drive of that capacity, or the drive is flawed.

I'd bet you dollars to donuts that all 16TB SSDs are fake...

https://datarecovery.com/rd/amazon-continues-selling-fake-flash-drives-and-ssds/#:~:text=16TB%20SSDs%20are%20scams%2C%20even,too%20good%20to%20be%20true.

I am having the exact same issue and have not found a resolution. The brand is Integrated technology express.

I have run disk first aid and techtool pro and the drive passes all tests

gtole wrote:

I am having the exact same issue and have not found a resolution. The brand is Integrated technology express.

Never heard of them. And I've seen a lot of SSDs. If it were me I'd return the SSD for refund and buy something known to be reliable. Samsung, Crucial, OWC, WD, even PNY.