If you see this message when trying to copy very large maps to your SD card then please check the following:
1. Check your SD actually has enough free space. You can normally do this in your device settings or via a card reader on your PC just right click the SD card drive in File Explorer and choose Properties.
2. Check which file system your SD card is using as they are normally pre-formatted as FAT32 which has a 4GB file size restriction even if the card itself is much bigger.
Tip: The exFAT file system does not have a 4GB file size limit. You can use your PC to reformat cards from FAT32 to exFAT but this will delete all existing data on the card. You should also check your device specifications online to ensure your device can read exFAT formatted cards.