Running Low Can Bring You Down
Whether you find Google's Play Store won't allow you to install a new big game, or system updates are failing, running low on storage space can cause your DroiX® all sorts of problems.
Rather than factory resetting, finding the directories where these files are stored can be enough to determine whether they are safe to delete or not.
The following screenshots take you through the process, you just need to open ES File Explorer (click the little circle with six dots, or the My Apps/Apps icon, then ES File Explorer's icon).
From there, close any introductory messages that appear the first time you run the app. Don't worry about installing an offered update for ES, until your storage space is restored.
Click on the TOOLS menu in the left hand menu, to expand it, then select the SD Card Analyst option.
Wait for the process to complete, then scroll down the long list until you see All Files, click the Details link.
Now drill through the directories offered. Those taking up the most space will be at the top. I've skipped some of the folders in the screenshots below, but in this (set up) example there were some very large files in Kodi's temporary directory.
Once the culprit(s) have been found, check whether they are safe to delete. If you're happy it will be OK, click on one or more file, then the Delete option at the bottom.
That's it, you're done!