Chosen Solution

I’m upgrading the 256 SSD drive to the 512 . but it does not have metal cover how do I remove the one that came on the 256 stock?

If you have a Mac Pro tower system as pictured to the right here then you’ll need to follow this IFIXIT guide Mac Pro Late 2013 SSD Replacement. The metal cover (heat sink) on the SSD unit is part of the unit (Apples part). Are you sure you have the correct replacement part? You need a special M2 PCIe SSD unit so far there are only a few suppliers for this part make sure you have the correct unit. Update (05/04/2016) Well OWC has created a upgrade option here it is: Aura SSD for 2 Generation Mac Pro

I had success in taking of the protection / heat sink using a hair dryer a metal spud and a laser infra-red thermometer. Once my hair dryer was not so strong temperature didn’t passed from 70o Celsius I didn’t wanted the ssd hotter than 80. C. After some minutes it realized With little effort on the spud. I did it to use the ssd from the mac pro in my Macbook Air 11. I don’t think it is necessarily to use that plate if you upgrade your mac pro. it doesn’t seem to be a heat sink since it is plain and it is glue with 2 stickers. It will not cooler the ssd, maybe will even keep the heat inside of it since it is a air cushion

I used fishing line to remove mine. 15 lb, doubled up. I wrapped one end around something stationary—in my case a dumbell, and the other end around a screwdriver so I could comfortably hold it taut. The doubled-up line stretched only about 18-24”. I slipped the line into the gap between the chip and the metal cover, and carefully worked it over to the spot where the cover is glued to the chip, pressing it into the glue. At that point, I gently, but firmly slid the unit up and down the line, working it like a saw. I could feel it gumming up, and I could see it leaving bits of the glue on the line. I continued this way, cleaning the glue off the line as I went, until the line broke all the way through. There was some gum left on the SSD, but that all scraped off. It took me about 10 minutes to break through the glue and get the cover off.

I just hit it on the ground and it worked for me