I'm running Tor 5.0.1 on an up-to-date Kubuntu system. Normally Tor runs fine; I route Thunderbird through the Tor port as well, and everything runs smoothly. But in the last three or four days the Tor browser has slowed to where it no longer loads any web pages more complex than Startpage. The browser starts without complaint and visits check.torproject.org successfully. Anything more complicated than that, and the browser times out. Since Thunderbird is using the same connection, email sometimes times out as well.
It's been fine for a very long time and only started timing out in the last few days. I read something about clearing state files, but I don't know where they are. Can anyone advise, please?