When I first made this thread, I had just reflashed my phone and installed a new ROM to get around the issue as a quick and dirty fix.
Unfortunately, the problem has resurfaced, and in this instance, no app was updated or changed to cause this issue - it just happened spontaneously happened again.
I still have TWRP 22.214.171.124 installed, and none of the following have worked:
- Wiping the cache.
- Wiping the dalvik-cache.
- Fixing permissions.
Research tells me that the "Fix Permissions" option has been since removed from CWM as it is now obsolete.
I would like to note that when I reboot my phone, I will get the "Unfortunately..." error message at the lock screen (the system UI will appear in the background and then crash), but when I use the power/lock button to lock my phone/turn off the screen and turn the screen back on (turning the screen back on can take 5-10s), it does stop the message from occurring at the lock screen (i.e. until I can enter my PIN).
Does anyone have any other solutions?