Disting Mk4 SD card troubles

Hello, I hope I can get some advice here. I have a Disting Mk4 which seems to have developed an issue with the SD card reader.
I have 32Gb SD card that previously worked fine but now upon start up the Disting will show an empty screen after showing the firmware version (4.18). It does not react to any button pushes or turns.
The module starts up fine if the SD card is removed. The SD card reads fine on my mac but fresh format as per manual does not help with the Disting startup. Unfortunately, I do not have another card to hand to further check this. Has anyone else ever had this? Could the card reader in the Disting have failed?
Thanks in advance for any help or advice!

I have not had that happen before (I have several Distings). You don't mention what kind of SD card you have, but if it's not the specific type that the manual recommends then I would get one - they're not expensive. If you still can't make any headway then I would contact OS at Expert Sleepers, he will be able to help you better than anyone on here.

Thank you for reminding me - I did intend to mention the current SD card is some no-name product. I will give Sandisk a go. Cheers.