A lot of people have been saying they were unable to get a 64mb micro sd / sdhc / sdxc card to work in the SJ5000+ sports action camera. Indeed the manufacturer website even states that max supported memory is 32gb. There is however a workaround which will have you up and running with a 64gb card in less than 5 mins.
First off, update your firmware! The latest version is v2.6 and can be obtained here: http://www.sjcamhd.com/news/sj5000plus-v2-4-version-firmware-download/. Be sure to download the correct version for your camera and follow the installation instructions carefully.
After successfully completing the firmware update and ensuring the camera is functioning correctly, take your new 64gb card, connect it to your PC using a card reader.
Next point your browser to Ridgecrop Consultants and download their GUIformat utility.
Open the file, be sure to select the correct drive letter for your memory card. Leave the allocation unit size as the default 32,768 and check ‘quick format’ if not already checked.
Click start and within a few seconds your card will be ready. (Be aware that this action will wipe all files currently on the card)
When it has finished formatting you can return the card to the camera and it will register as 64gb and you’ll be ready to start shooting.