Ricoh Theta Converter on Mac dumps large files

Hey folks. Having an issue with the converter app. Have transferred two large video files from Theta V today, put through the Ricoh Theta app to do initial conversion to the _er file type, then want to run through Theta Movie Converter to get 4 channel audio for Premiere edit. First file worked OK at 6GB, but the second (11GB), when I go to save the file, just throws up an error box reading “Disk space is not enough”. It won’t do it no matter what I try, and I’ve a good 320GB available on the drive I’m using. Any thoughts welcome - I’ve logged a query with Ricoh, but… well, we’ll see how that turns out.