I apologize if this has been covered already, but i've posted on other threads and haven't gotten any replies yet. This issue has been frustrating me to no end. I have the regular Maxx, which came with a 16 gb class 4 Kingston card. I decided to upgrade a couple months ago to a 32 gb because I was running short on space. I never had a problem with the 16, nor do i now. I bought a Kingston 32 gb class 4 card and it is very finicky. I can put data on it by using the adapter in my card slot on my PC with no problem, but after I put it on the phone, things disappear and the phone won't even let me delete things a lot of the time. I have been trying to find a straight answer on compatibility, but apparently that doesn't exist. At least not, short of calling verizon and/or motorola. Based on what I've been reading on this thread, i'm wondering if its a class issue. Any help is greatly appreciated.
Hmmm. There are sometimes problems with correct formatting if you just load up the card on a PC and then drop it into other devices. The first time you use it you should format it on your Android device first. Then I'd recommend plugging your phone directly into your PC and transferring to your SD card through the phone itself. This should negate most formatting issues right off the bat. Also using a file format that can be read by Android can solve other formatting issues.
For example, the stock Android video player doesn't like some files, (like .flv, .mkv, .avi, etc.) so finding an app that can open and/or play the files is needed sometimes too. For example, I use BSPlayer for all my video files (like I listed above) and it's a champ!
Unfortunately, Google made Android 4.0 + with reduced SD card support, and you can't move apps to the SD card (unless you're rooted) like you used to be able to. And finding the actual SD card on your PC might be a pain in the butt since Android 4.0 + now uses a virtual SD card, which is really internal storage, and looks really confusing while using a file browser. But transferring via your phone should work well.
I also recommend using a cloud service like Dropbox, Box, Copy, or Google Drive (I use all four!), since they make file transfers cross platform easy! BTW, Copy has no file size limits when using the mobile app or their desktop client, so storing and sharing large files just got easier! But download times still suck, and a wired transfer for files like movies or music is going to be faster. Still, dropping a word doc in my Dropbox folder on my PC makes that file nearly instantly available on my phone now too.
Anyway, hope this helps. If you're still having issues say so and maybe we can help you troubleshoot some more.
Edit: I forgot to mention the Airdroid app. It's great for not only transferring files, but you can even remotely access your pictures, videos, and other files. Download or upload anything, and perform security tasks like locating a lost/stolen phone or remote wiping all the data. It's still slow for large files, but it's a no hassle solution. Just watch your data use when transferring files as that can eat up a data plan fast.
Also of note, I've been having problems with the MTP protocol and getting my Windows machine to recognize any of my Android devices. I don't have a workaround for that yet, but I thought I'd share just in case anyone else was running into that problem as well.