Going from KitKat to Lollipop and losing 20 GB of storage

[ddr3202]

My Specs

Model: Nexus 7 flo (WiFi only)
Android 4.4.4 KitKat
Kernel Version: 3.4.0 g03485a6
Build KTU84P
Use TWRP as my Recovery

I purchased my Nexus 7 in September 2013. I went ahead and rooted it and later installed Android 4.4.4 KitKat and CM11 with the gApps. Everything was fine. I still had 32 GB of space on my system, of course I had some apps and media stored in this space. I was running this for over a year. Everything was working fine.

I then decided to upgrade to Android 5.0 then 5.1 (Build LMY48G) with CM-12.1 the the gapps this past week (8/10/15). I was surprised to fine now I only have 12 GB of storage. What happen to the other 20 GB of storage? No problem with my media as it was backed up.

I then decided to un-root my Nexus 7 flashing the stock OS and ROM back to Android 4.4.4 then re-rooting. Everything seems to be fine except I still only having only 12 GB of storage. O Problem NOT solved!

I guess my question is how can I reclaim the lost 20 GB of storage? Thank you for any suggestions you may have. Oh, I used at all times the Nexus Root Toolkit and TWRP to preform the rooting and un-rooting process.

 

[Spoderman21]

I think the reason for losing all that space was from the new update files I had the same problem when I upgraded my phone. I had 21GB of space before the update, then when I saw the space after the update I have 15GB Now.

Posted via the Android Central App

 

[anon(480526)]

A factory reset or two usually does the trick for me. Go into recovery and clear your cache while you are at it also.

Not only will these help with the missing storage, but some people report it being required for Lollipop to run smoothly. I did not have any luck and went back to 4.4, but best of luck to you on yours.