Currently the only external device that NCTech can verify will work with iSTAR Pulsar+ without issue is the Samsung T5 SSD, either 250GB or 500GB:
This must be formatted to NTFS* and use it's own supplied USB-C to USB-C cable shown above to connect directly to the iSTAR Pulsar+ device.
While it may be possible to use alternative external devices in conjunction with iSTAR Pulsar+, behavior may be unpredictable and NCTech cannot support their usage at this time.
Note that MacOS machines are by default unable to format an external drive as NTFS. Mac users may consider using a 3rd party application such as Microsoft NTFS for Mac by Paragon Software.