Problems? Solutions!

Data connection problems:
Simple: If you unlocked with Freegee, Hopefully you have an EFS backup that you can restore. Reboot when done.
Check bottom of post to get Freegee to work.

Grab a stock ROM for your device
Make a recovery backup of your CM ROM.
Wipe data, cache, and dalvik cache.
Flash the stock ROM
Update PRL, update profile, get a strong GPS lock (GPS status & toolbox app)
If data hasn't returned at this point then you have a corrupted EFS. Hopefully you've unlocked with freegee and have an EFS backup that you can restore.
Restore recovery backup of CM.

Crash loops after enabling ART: use Aroma Filemanager or TWRP filemanager or adb shell to delete '/data/property/persist.sys.dalvik.vm.lib'
then reboot

android.process.acore has stopped unexpectedly: make backups of contacts, go to 'settings>apps>all>Contacts Storage' and clear data. reboot to recovery and wipe dalvik and cache.

Freegee saying device is detected as LG-gee and unsupported: edit /system/build.prop and change "ro.product.model=LG-gee" to your phone's model. Like the following example:
Sprint Optimus G - UNOFFICIAL CM11 - gee base
Epic 4G Slide - CM11
2x HP Touchpad - CM9