By loading erasable data, any type of data or files can be put onto a flash drive, giving the user the option to erase them, so that space can be made in the memory to be used freely. By loading non-erasable data, instead, your files will be placed in a partition of the chip that is separated from the free memory, and you will not be able to erase the data, not even through formatting. When you insert your USB flash drive into your computer, two icons will appear: a read-only one and a removable mass storage one, which can be used freely. The pre-loaded data will occupy the available memory on the chip capacity you selected when ordering, so if you choose the "non-erasable" data service, remember that the free memory space will depend on the size of the file you want to pre-load.