sd card is blank

If it was encrypted in a diffent device, or encrypted in that device. It won't be readable by another device. That is the most often answer to that question. If it was, then it will be permanently married to said device unless it can be formatted (erased and reset to accept info). If your just trying to move stuff from one device to another, attach said device (with SD card installed) to PC, download. Attach other device to PC and download from PC to device. Hope this helps