Solved! Go to Solution.
I had the same problem and tried all this stuff but what finally worked for me was: go to settings, select apps, select Spotify, select clear cache, select clear data & select uninstall. Then go to settings, select storage, select unmount sd card for safe removal & remove sd card. Leave it out while you reinstall Spotify. Check to make sure it's working correctly, if so, turn off phone, reinstall sd card, power on phone and you should be good to go.
I've updated my S5 over weekend from 5 to 6 android. Had exactly the same error.
However, my fix was simpler. Maybe there is newer spotify version already, which solves half of the hassle.
In my case:
And it's working. However, currently I have no premium, so maybe the fix in my case was simpler (no need to download songs for offline listening).