I can't format my SD card I just inserted a new 16 GB SD card in my AT&amp;T Galaxy S5. I'm trying to format it but it's asking me for a pin and I don't know what it is its not the last 4 of my phone number and it's not my last 4 of my ssn. Please help!
The fastest thing to do is to insert the 16GB SD Card into another phone, a digital camera, or a computer SD card reader, and format it there.  You'll get the job done faster than any other way.

If for some reason you are set on using a pin, you can try 0000, which works in some cases.