The full text of the phpMyAdmin complaint is ...
There was a problem accessing your browser storage, some features may not work properly for you. It is likely that the browser doesn't support storage or the quota limit has been reached. In Firefox, corrupted storage can also cause such a problem, clearing your "Offline Website Data" might help. In Safari, such problem is commonly caused by "Private Mode Browsing". '
And it shows up every time I do anything at all in phpMyAdmin. I've tried emptying the cache and local storage - which was empty anyway - but no joy there. I don't find that I have disabled local storage anywhere.
I've just installed phpMyAdmin, working against a local MySQL installation. Seems to work ok ... but I get the complaint on every single thing I do in phpMyAdmin.
While I'm here let me ask about the debian-sys-maint user with all privileges on the MySQL installation. I certainly didn't create that. I don't see a way to delete it either.
Not sure what the root cause of this error was (maybe an unfortunate Firefox crash) but getting rid of persistent site-related storage from my Firefox profile solved this for me.
Open your profile folder and get rid of the following:
On Mac OS X you can find your profile folder as follows. In terminal type the command:
Then look for the current profile folder, which looks something like
86fdt4d.defaultNOTE: by removing these files you will remove all of your site visits (history) and offline web app data so make really sure that you are not deleting any essential data before continuing...