It seems that the Windows drivers are different from the MAC drivers. With the MAC driver macOS will see a Pegasus 1. But I just tested with Windows 10 and the latest driver and neither a Pegasus 1 or a Pegasus 2 was recognized. The Pegasus32 comes right up, as does a Pegasus 3. The only difference is that I am connecting the Pegasus 1 and Pegasus 2 with an Apple TB2 to TB3 adapter, which should not be a problem.
I tried loading the Pegasus 1 Windows driver, but it did not help.
I will make some inquiries.
We have never tested with any Thunderbolt HBAs.
My Windows 10 PC contains a Sonnet Technologies USB3C-2PM-E but no Thunderbolt 2 interface. To connect my Pegasus R4 to the Sonnet card I'm using a StarTech.com Thunderbolt 3 to Thunderbolt 2 adapter.
Upon rereading, I think I see the problem. You may have a USB-C type connector on your computer, but it is not Thunderbolt, so the TB3 to TB2 adapter won't work. It will only work if you connect it to a thunderbolt port. The Pegasus32 will work with a USB connection through a USB-C cable. The Pegasus 1 requires Thunderbolt 1 (or TB2).