@Tony I deleted File Explorer and did a second round on File Browser. I found that specifying a SSD as the connect target did not trigger the 'user name' issue. it's a Samsung SSD and an iPhone 8...

Samsung 1TB SSD on the USB of the AX3000 using File Explorer (free trial) on iPhone 8 works fine for .txt and .rtf and .jpg - but .mov video files frequently lock up the app - just the spinning...