I also had this issue with my X-T2 saying:
"No memory card - Insert a new card"
This is the first time I have encountered this with my camera. I am using a micro SanDisk Extreme Pro 32GB V30. My MacBook Pro was able to read this card through an external card reader but my camera was not able to.
I have tried 2 other Sandisk cards and they work just fine.
Please help!!!
Thanks.