Hi @thermokarst
I re-downloaded the file & was able to convert it successfully. The first time I tired to upload this file however, I (when running the same command) got an error saying that the file was not in TaxonomyTSVFormat. I opened up the file to look closer, and found that one of the lines did not have a tab between the accession number and the taxonomy, so I added one. The file could then be recognized as a TaxonomyTSV file but generated the TypeError. So, in short, I modified the file, but I'm not really certain what happened beyond that or why it worked the second time.
Thanks for your patience