ITS NOT A ROOT PROBLEM.....!!
YOU DO NOT HAVE TO RESET YOUR DEVICES OR TAKE ANY SUCH DRAMATIC MEASURES..!!
Your Card is simply NOT recognised by your Device because its NOT Formatted to the Device acceptability Standard....Format to correct Standard thats ALL you have to do..very simple really.!
Most SD or microSD Cards come out of Box not always Formatted to the standard you require for Android..!!
If I remember correctly and am not mistaken you will have to format to FAT32..on your PC..if the Android Device does NOT recognise your SD Card and Install/Format automatically thru the Device.!
Some PC OS versions will NOT format certain size Cards ie...WIN XP.
In which case you will need a programme called Easeus Partition Manager its a Formating Software and its Freeware.!!......you should read the How to before starting..OK
Install and Follow instructions its fairly simple...to use.
Saying that you should try SDXC Cards...I am using micro64GB in FAT32 SDXC cards in both my S3 phone and Tab2 10.1 and both working perfectly.I know they are more expensive but you only need one...the right one..right.?
Have personally NOT tried SDHC cards...I thought these were not Fast enough for Android Devices and only used in Cameras etc..!!
Check it out and hope you fix your problem.Let us know how you get on..!
I am confident it will work when Formatted correctly.!
Here is a nice Link have a Read all about Formatting for Android Devices.