For some users in FF 70, QuotaManager was broken and caused the new implementation of local storage (LSNG) to fail, as well. Therefore we disabled LSNG on 70 with bug 1592136.

As the failure seems too rare to be caught on Nightly, for the time being, we keep it on in beta 71 in order to gather more feedback.
If you encounter symptoms like partial site loading or missing functionality as in
bug 1591081, bug 1591170, bug 1591332, bug 1591374, bug 1591517, bug 1591530, bug 1591547, bug 1591684, bug 1591723, bug 1591777, bug 1590804
please do the following:

1. Point your browser to https://firefox-storage-test.glitch.me. You should see

Overview:
Storage is working. This is your first visit or all storage was automatically cleared.
Specific Subsystem Statuses:

LocalStorage
    Good: Totally Working. (fullyOperational)
QuotaManager
    Good: Totally Working. (fullyOperational)
IndexedDB
    Good: Totally Working. (fullyOperational)
Cache API
    Good: Totally Working. (fullyOperational)

If it looks similar (all fullyOperational), you do not have encountered this issue. Feel free to file a different bug.

2. If it is reporting problems, or does not display anything meaningful after some second, please take a screenshot and add it to this bug with a comment on what you tried to visit.

3. (optional) Please make a copy of your browser profile folder and put it aside, which could help us with further investigations once we know, what we are looking for.

4. Disable the preference "dom.storage.next_gen" in about.config (set it to false) and restart the browser. This hopefully restores functionality for most sites.

Please note that this is just a workaround and on some sites (making use of IndexedDB or DOM caching) you might still encounter problems. Starting with a clean profile could help in these cases.

Thank you for your help!

Debug Info:

storage.estimate() threw: Internal error while estimating storage usage
Failed to create "persistent" IDB.
Failed to create "transient" IDB.

{
"v": 1,
"curVersion": 71,
"prevVersion": 0,
"ls": {},
"qm": {
"lastWorkedIn": 0
},
"idb": {
"persistentCreatedIn": 0,
"persistentLastOpenedIn": 0,
"clearDetectedIn": 0
},
"cache": {
"firstCacheCreatedIn": 0,
"unpaddedOpaqueCreatedIn": 0,
"paddedOpaqueCreatedIn": 0
}
}

Firefox Developer Edition, 71.0b7 (64bit), on aurora channel.

Just reboot the PC and a few site stop working correctly. Like imgur.com (can't load the pictures), and gitlab.com can't render a few sections. Saw NS_ERROR_FILE_ACCESS_DENIED in the console (developer's tool) on both site.

LSNG has been disabled in 71, bug 1594299.