Can't save anything to sd card I have an HTC desire 320. I just bought from a koodo stand and the lady talked me into getting a 16g sd card and I didn't even notice till my internal storage was full that it pretty much doesn't work so far I have a notepad app a messenger app and a photo app on it using less than one gig but other than that nothing will save to it even if my internal storage is full and sometimes it randomly unmounts it's self. I've tried everything I could but nothing seems to work.
Since Android 4.4.0 Kitkat, Google has disabled the write permission by default for security measures.

Since the HTC desire 320 is shipped with Android OS, v4.4.2 (KitKat), you can't write to the SD-card by default.

If you want to get the write permission back you must root your device and use an app such as SDFix. You also can manually edit the permission list when you are rooted, but it will be reset every power cycle.