Connecting my phone via the USB as "PC connection" on a Windows PC is fine. The 64Gb SDXC is handled correctly and copying and deleting files to the jolla is fine.

However it is not fine under Linux - more specifically Fedora 19. I installed on the desktop computer:

fuse-exfat-1.0.1-1.fc19.x86_64
exfat-utils-1.0.1-1.fc19.x86_64

and while it shows both phone storage locations in the File Manager correctly copying to the 64Gb sdcard fails. Often it refuses, but also it quite often says that it has done it and instead the files have copied to the other storage location /home/nemo

As a result of these problems I lost all of my config data /home/nemo for contacts, call list, txts etc etc and it wiped out the default directories in /home/nemo. It deleted accounts and also screwed contacts so even when I try and re-import contacts it still says there are no contacts......Grrrrr. Bitter lesson.

I have resorted to connecting the phone in developer mode and scpping the data to the 64Gb sdcard.

In theory given that exFAT support was installed correctly on both jolla and desktop it should be fine.

There is something funky going on though on Fedora 19 as it believes the cards are camera devices and often it tries to connect to them with gphoto2://

Anyway thought somebody might like an update on how I got on with 64Gb SDXC

Oh havent tried MAC yet..........