Null read id assigned to taxonomics

Hi,

I have some problem in MEGAN6, I try to extract read id (.rma file from .daa file) by use export text > readName_to_taxonName but the result from it shown some read as “null” but it can assign to taxonName (it also on readName_to_interpro2goName), so what the maning of null can I discard it or not?

Thank you for your help:grinning::grinning::grinning:

could you please give me access to an example file
D