I want to start off by saying that I am extremely upset! About three months ago I purchased a brand new Crucial 256GB M4 SSD to go with my top of the line 15.4" MacBook Pro. Unfortunately, the drive failed and after wasting several days troubleshooting with Crucial's technical department and losing a lot of irreplaceable data, it was necessary to return the the drive for replacement. I shipped the drive on 5/10 and received the replacement drive on 5/25, 15 days later. That was a long 15 days without a computer that I needed daily for work. Yesterday, while installing the drive, I was shocked and extremely disappointed to see that the replacement drive was refurbished. Seriously, I get a refurbished drive to replace a 3 month old defective unit, that's absolutely horrible. When I think of a refurbished item, I feel like I am getting someone else's defective item. Well guess what, the replacement drive didn't work either! Whoever refurbished it did a lousy job. At this point I have no faith in the reliability, warranty, or customer service of Crucial when it comes to the M4 SSD, hopefully the RAM that I have is not as bad! I have always purchased Crucial products due to the reliability and quality of the product but it seems things aren't what they used to be. I am not exactly sure what I am going to do at this point. Even if I am sent a brand new drive, will it be reliable? I don't have the time to constantly be swapping and waiting on drives. I need something that works. More than likely, I am going to throw the refurbished drive in the garbage and never purchase another Crucial product again. I guess this would be the excuse that I need to upgrade to a larger, more reliable, and faster Samsung 512GB 830 SSD.