Humax 9200T erased all recorded programmes?

We have had a Humax 9200T Freeview PVR for several years. Sometime today between mid afternoon and early evening the box seems to have lost all of our recorded programmes. The list of recorded items is completely blank with nothing listed. The bar graph showing disk usage is correct showing about 26% free space.

Is there anything I can do to get my recorded programmes back, or will I have to use the Format Button?

(I am using the latest firmware, I've checked the Humax site.)