VeraLite suddenly stops recording log activity

I have a number notifications setup that email me an alert and log the activity.

Until today, that is, when it just stopped recording activity (in the log tab of the device window to be clear). The emails get sent correctly it is just that the logs are blank. Also all history vanished as well.

I record to a USB stick so I thought it had fried so I went through the steps to remove the USB (reboots of course) and did a test to see if logging had been restored, and no it had not (however email was sent)

So I put the USB back in and it did it’s thing setting up the USB stick which it said was successful and did a test, email sent, no log recorded.

Anyone have any ideas on this?