If an SD card is formatted on a Windows PC, it may have defaulted to using the exFAT filesystem (the latest incarnation of the Windows FAT based filesystems).
If you put an SD card which is formatted as exFAT into the HX-1 it will not be recognised by the HX-1.
An SD card must be formatted as FAT32 for use within the HX-1.
Large SD cards (64GB and larger) MAY work in the HX-1, but your milage may vary, depending upon many factors, including the quality of the card.
If you attempt to format an SD card of 64Gb capacity or larger on a Windows PC, Windows will not allow you to format the card as FAT32. It will allow exFAT only.
There are "tricks" to allow formatting as FAT32 on larger SD cards under Windows. Search Google for a solution in this case.
If the steps above do not resolve this issue, please contact our technical support team for further assistance.
You can submit at technical support ticket via our website at http://hema.helpserve.com/Tickets/Submit