Internal memory issues So I have a ZTE obsidian (z820) running lollipop 5.1 and I have a 16gb micro SD card in it.  There is no way to root this phone that I have found after weeks of searching,  and I need to move my apps or at least install new ones to my SD card.  Under "default write disk"  I have the SD card checked off, but the phone still tries to install the apps to the phone.  I've rolled back all the apps I don't use that come stock to their stock versions and disabled them to free up some space and I use the apps I have (not many) but I still get insufficient storage error when I try to install apps.  Even internal memory has over 300mb free yet apps only a few megs refuse to install until I delete stuff.  Is there anything I can do to remedy this situation??  

I've searched around any have no idea what to do.
For insufficient memory over 300 mb has a reason of storing space for images and videos captured by camera.It is specially allotted to them as for camera internal memory is default as storage. There should be an option for changing default write disk for camera. By changing it might help you.


For the rooting your device you also willing to try these -->  


1. Rooting tutorial.
2. Upgrade to Marshmallow.