The partition that Lightning server try to read is read-only. Lightning server can not create particular flag file on the partition for proper operation.
- Please make sure the USB drive's partition is supported by Lightning server. The partition could be FAT32, exFAT, NTFS, ext2, ext3, ext4 and OS X HFS+.
- If you are using an SD card with card reader, please make sure the write-able protection switch has been placed on 'OFF' position.