External SATA drive not showing up when connected via USB adapter I've got a PATA/SATA adapter which connects via USB, and if I connect PATA drives to it they show up fine, but for some reason SATA drives aren't working. If I connect the same SATA drive to my Windows box it also shows up. Does anyone know what the cause of this is, and how to fix it?
This is on an older MacBook Pro (mid 2014), running High Sierra v10.13.6.
Assuming you’re using the same USB to PATA/SATA adapter on both the Mac and the Windows there are a couple factors which could contribute to the symptoms you’re seeing:

the USB to SATA bridge doesn’t use the universal driver that’s included with macOS. There may be a specific Windows driver for the SATA bridge. The PATA bridge may use the standard driver, which is why it works
The device may be for Windows and not compatible with macOS
The SATA drives may be formatted using a filesystem not compatible with macOS (i.e. Linux Ext2/3/4, btrfs, etc.)

Before you decide that the drive or device is not functional, you can parse dmesg to see if the device was detected.  You can also issue the command diskutil list to see the disks detected by the OS.  It may not be able to read the file system, but it will be detected.
Additionally, since this is attached via USB, you can use system_profiler to view all attached devices.  Just issue the command system_profiler SPUSBDataType and parse through the output, looking for your particular disk drive make, model, and size.