Hello!
After having my shield since 2017 or so, I started getting a "storage too low" error about a month ago. I had been able to stave it off by clearing the cache and calling it a day, but this morning it said it was "critically low," which it has never said before.
Going into the storage details , it says that of the 12 GB onboard, 3 is used for apps, 121mb is used for Cached Data, 434kB for "Misc," leaving only 81MB available on the system. I may not be the best at math, but that is only accounting for less than 4GB of data, I have no idea where the other 8 are. Clearing the cache has only moved 100MB from cache to available, which is far from clearing the error.
I don't use this as a plex server, it is used for streaming only from all the usual suspects (Youtube, Netflix, HBO Max, etc). Has anyone else dealt with this and know how to clear this out?
Update: I went nuclear and factory reset it. After redownloading everything, I have 10GB available. A bit annoying, but definitely does the trick.
You might have a lot of hidden cache that is not visible by looking at apps details. I would download an app like CCleaner or similar that has a Hidden Cache cleaner option.