If your Nike+ FuelBand SE or first generation FuelBand displays a LOW MEM message, your device's memory is nearly full.
Please connect your device to your computer. This will allow the Nike+ Connect software to upload your NikeFuel and other activity data to your account, clearing memory on the device to enable continued and uninterrupted use.
Note: If you have not yet installed Nike+ Connect, you'll need to do so in order to sync your data. Here's how.