I have a Nikon D850 and have been using a Sony 120GB XQG card without any problems for over a year. I recently purchased a SanDisk Extreme PRO 128GB CFexpress card. When I insert the card into my XQD card reader it does not show up on my desktop. I then put the CFexpress card back into the D850 and connected it to my imac 27" and still no luck. My imac is running 10.15.7 and the D850 has the latest firmware. I'm have a hard time finding answers on the internet. I reached out to SanDisk and all they said was to return it to where I purchased it, or send the card back to them. I am not getting any answers as to why I am having this problem. So my dilemma is, do I wait and try to iron out the SanDisk issue, or do I return it and purchase a Sony card? What guarantee do I have that the Sony will work?