My phone had a bug that said: "Insufficient internal storage", so I tried to solve this rooting with TowelRoot, but when I did things became worse... Now, it seems I can't access internal storage.. if I try to save anything (image, music, etc) to it, it crashes, it just says: "Unable to save file, try again later" if its from WhatsApp, if I try with chrome it closes, if I try with the computer it stays some time trying to copy the file then it says it cannot do it. After this, I did a Hard Reset (power + up volume buttons), but that didn't do it... What can I so now to access the internal storage and be able to save files again?
Try installing SuperSU from google play. SuperSU has an option to unroot. Try multiple times (if it doesn't work once) and reset the phone this fixes the internal memory problem.