I am having the same issue using a SanDisk 32G microsd. Roku 3 doesn't recognize the disk. I have formatted the disk on my computer but the disk is not recognized by my Roku 3. Any advice would be helpful. Thanks. Sheenders
I'm glad Roku finally mentioned to someone that it was a size limit - thanks for the post! It would be nice if they updated their website as a requirement. I just discovered you could use any size card over 4GB, if you can't find a MicroSD card that size anymore, or if you already purchased a larger one:
Delete the existing partition on the MicroSD card and recreate only one partition that's 4GB (4096MB) in size.
I left the volume label blank, left segment size to default, and drive letter doesn't matter. On Windows 10, you can find this utility by right-clicking on the start button, and selecting Disk Management. Caution! make sure you don't reformat the wrong media, like your C: drive :-)
Afterwards, insert the card into Roku, and select system restart. It worked for me, hopefully for you as well.
I am having the same problem. I have a new 16 GB micro SD from SanDisk. I've tried changing the partition size to 4 and even 2 GB, formatted as FAT32, but my Roku 3 still does not recognize the SD. I am about to give up on this.