I was a bit concerned when I first ordered this microSD card.  Samsung's documentation says it is compatible with an SDHC card, but this one is SDXC.  I read a bunch on Google about incompatibilities, but they were older forum discussions.  I read the SDXC used to be incompatible, but that Samsung published an update late last year that allowed the Galaxy Note 10.1 to work with this card without the need for reformatting to a FAT file system.  For the price, I thought I didn't have much to lose and would give this a shot.My report:  The Galaxy Note 10.1 read the card perfectly when installed.  There was a small glitch where the Note asked to format the card after I removed it from the tablet and transferred about 25GB of data to the card (from my PC while it was in a card reader).  All I needed to do was to remove the card again, and reinsert and reboot the tablet, and the problem went away.  Have been using this for hours doing extensive read/writes to the card with no failures.  Will update if I have any issues, but for now, I am extremely pleased with the performance on this.