You can use the sd card for music, pictures and movies, but not to store apps unless you jail break, then you run into other problems.

Other than that, I have found that any micro sd seems to work, I personally use a micro sd with a speed rating of 10.

 

My phone seems to choke on a 32gb card. I loaded about 20gbs of music on one and while it reads fine on my laptop and a pmp (Cowon J3) It works for a short time on my RazrM and then starts giving me read errors and occasionally just shows the whole card as empty. If I unmount the card remove it and power cycle the phone it will work ok for a few hours and then quit again. I swapped the 16gb card in the pmp with the 32gb and the pmp can read and play music off the 32gb card with no problem, ditto with the laptop. The razrM can read and play music off the 16gb card with no problem. I am using Jet Audio, but the problem with the 32gb card also occurs with the native google player.

Could there be a limit on the number of files the razrM can access on the sd card? Anyone have any issues with 32gb card?

Any suggestions would be appreciated

 

I had the same issue. I replaced the SD card, put the same music back on the new card (about 17GB worth), and it works without a problem. I'd suggest trying a new card.

 

"jail break"? This ain't no i-fauxn

 

Yep - That fixed it. Can't quite get my mind around why a SD card will work in all other devices but not in the RazrM, but the new card (same make and model) works fine so I'm happy.