I've read through all this thread's posts and thought I'd seen the SanDisk Extreme and Samsung Evo cards being recommended as working. Sadly I've had both these cards from Amazon and had to return both as they appeared to format okay in the camera, but then the camera tells me about 10 seconds later that the card needs formatting.
So I emailed Thinkware to ask them if their cameras only use their own cards. There response was:
"The devices are not locked to Thinkware only SD cards. However we cannot guarantee compatibility of other makes of SD. 128GB Thinkware card and lower are purchasable below.
https://thinkwaredashcam.store/accessories/f800-pro/
Kind Regards,
Ryan (Thinkware Support Team)"
I initially thought, as many have speculated, that my camera being so new (purchased June 18), that I had the latest firmware and this locked out third-party cards. But I'm not sure now as so many others seem to have had success with the SanDisk Extreme and the Samsung Evo.
One anomaly I have noticed is that Thinkware's cards are marked as 'HC' (click the link above and see for yourself). I thought the HC spec only went up to 32GB, for larger sizes the spec is called 'XC'. I've not been able to find any other make of card that is over 32GB and a HC card. I wonder if this anomaly has anything to do with other cards not working like my experience.
I've resigned myself to the fact that I will just buy the Thinkware 128GB card, as I want that capacity and think other posters are right about having bought the Rolls Royce of dashcams, why would I then buy cheap accessories for it. I'm gutted, as I would have liked to shop around, but I just want it to work now and feel I've exhausted every avenue.
That's my two-pennies worth, for what it's worth.