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URL: smb://10.10.10.254/UsbDisk1_Volume1/
Issues
AppleTV clears it's cache which uninstalls Kodi's Add-Ons.
TvOS grants 500Kb of permanent storage. Everything else is in a "cache" directory which can be cleared by tvOS whenever it sees fit.
https://forum.kodi.tv/showthread.php?tid=329625
If you're stuck using a fire stick and are unable to upgrade to a better device, then you need to use the "EZ Maintenance" addon. You can set it to auto clear cache, but more importantly you can set the preset for running a weak device, which should increase your overall performance.
Install openwizard addon and set auto cleanup of cache on startup.
Installed EZ Maintenance, didn't help.
Turns out that if you have an update available, tvOS will clear out extra space. The solution is to turn on automatic updates. After an update, you'll have to reinstall your plugins. Without installing the update, tvOS will reset Kodi every day until you update.