I am having the same problem with my Droid Razr. I had the phone for about 1 month before I decided I should move stuff over to my card to free up my internal storage only to find out that I could not access my card. I checked every forum and FAQ to try and solve the problem before finally taking the phone in to a Verizon store. The rep took out my card and inserted his but my phone did not recognize his, either. He put me in touch with a Verizon rep and they ended up sending me out a new phone. When I got the new phone, I plugged in the SD card and it was recognized. Problem solved, right? Well, the very next day no card! Again, I take it to a Verizon store and after about an hour with the rep trying to figure out what the problem was (he actually put in a brand new card), he determined that maybe there was an app that was causing a conflict and suggested I do a hard reset.
After the reset, I could see the card and thought that maybe it was one of my apps that was causing the issue. I then began trying to reload my apps one by one to see if I could figure out which one was causing the problem. Once I installed "Brightest Flashlight", I lost my card. I uninstalled the app but still could not see/mount the card (it was still greyed out). Tried to do another hard which wouldn't work because I had SD card selected along with my internal for the purpose of erasing/formatting. Because it couldn't find the SD card, it wouldn't reset until I unchecked the SD card option. Again, I phoned Verizon tech support and the rep tried to find the problem remotely but once it was clear he couldn't do anything he asked me to hard reset again. I did the reset, could see the card and then began to install some of my apps (minus the flashlight app). After installing my Bible app, again NO CARD!!! I went back in to a Verizon store, this time just asking if I could switch phones but because it has been over 14 days since I purchased the phone all they could do was have another phone sent to me. I am beyond frustrated. I chose this phone over the iPhone because the salesman told me it was a superior phone. I have been EXTREMELY disappointed and just want a different phone.
To make matters worse, the rep at the Verizon store (the Verizon store on Davis St. in San Leandro, CA... you know who you are!) basically tried to tell me because he couldn't find anyone else on the internet with the problem, that my problem was somehow unique to me, even though I have had to different phones and two different cards! I am now awaiting my third phone and will see if I am really just that unlucky or if Motorola/Verizon just is not aware of this problem. Can't believe more people haven't figured this out. I'm guessing because people may not even think about accessing their card until weeks or months later? Sorry for the long post, but I am very frustrated and unhappy with Verizon right now.