Same error as reported and closed in other tickets.

• The specified file temporary://download_8.csv could not be moved, because the destination is invalid. More information is available in the system log.
• Error moving file

Error received wether commencing from the Convert/Home screen or after the first failure.

Attempted initially with the CSV from a PayPal export and after the error tidied it up and ensured no extra lines/spaces, etc. in Atom (text editor).