I upgraded my wifi system from Virgin router with wireless repeaters to a full One Mesh System using TP-Link Deco S4. Everything worked seamlessly apart from non of the new recordings were showing up in the local storage. I could view the live feed on the cameras and the early detection alerts were confirming that the motion was detected.

The fix I used:

1.Disarm the Cameras

2. Safely eject the USB stick

Sync Module -> Local Storage -> Safe Eject USB

3. Delete Sync Module

Sync Module -> Delete Sync Module

4 Reset Sync Module

Place Pen (or similar) in the reset port and hold until light turns red. Then wait for green solid light and blue flashing light.

5. Re-add Sync Module

Scan QR code on the back of the Sync Module and go through mini wizard

(Note: I had to turn off wifi on my iPhone for this to work)

6. Re-add USB drive

Insert USB stick back into Sync Module then reconnect USB drive in App

Local Storage -> Add USB

7. Arm System