Sony released a7S III Firmware Update 1.02 which fixes FTP Transfer and USB Tethering stability along with improved overall camera stability. For Mac users, I highly recommend updating now as this update will probably not be compatible with MacOS 11.
Benefits and Improvements
• Fixes an issue where FTP transfer could fail when used with some USB-LAN conversion adapters
Note: Not all USB-LAN conversion adaptors are guaranteed to operate properly
• Improves connection stability of USB tethering when using an iPhone
Notes: Currently, the USB tethering function does not support iOS 14
We recommend using a smartphone and USB cable that support USB-PD (USB Power Delivery)
• Improves the overall stability of the camera
Previous Benefits and Improvements
[All Previous Benefits and Improvements are also included in this Update]
ILCE-7SM3 System Software (Firmware) Update Ver. 1.02
MAC USERS PLEASE NOTE:
The latest Sony Firmware Updates are only compatible with Mac OS 10.13 – 10.15
1. Make sure the camera’s USB Connection is set to Mass Storage
2. WITHOUT CONNECTING THE CAMERA, Click on UpdateSettingTool.
3. Once you see this message, connect the camera.
4. Follow prompts to begin the firmware update. Make certain to follow instructions in the linked post below.