@Taxachusetts
It should not matter which format you use to upload files or data to TT. A strong IT security setup would require that the files or data be loaded onto a containment server which is isolated and secure from the main system. Files or data containing any known malware will automatically be quarantined and not be allowed to pass onto and infect the main system. TT and other tax prep / filing services have been around for years and the likelihood is that they have to ensure that all data transmitted to the IRS is vetted as malware free.
