Andrew, I tried the manual change ("self._cache_limit = 0" -> "self._cache_limit = 1024*1024") and it still didn't get past "step 0 of 4" in 14 minutes, after which I killed it.
Andrew, I tried the manual change ("self._cache_limit = 0" -> "self._cache_limit = 1024*1024") and it still didn't get past "step 0 of 4" in 14 minutes, after which I killed it.