Can't install apps!! OUT OF SPACE error!! HTC DESIRE 626
(from an Android 4.4.4 user on a Nexus 7 2013)

I began to have this problem after installing the Xposed module "XInstaller". I uninstalled that module and everything went back to normal.

Important: It can get easy to confuse all of these X words. It wasn't "Xposed Installer" that was the issue. The issue was the module for Xposed called "XInstaller". This module lets you change some of Android's default app installation/uninstallation behaviors. For now, I'm leaving that module alone.