I'm seeing a massive stream of them continuously:
10/03/15 3:14:24.080 pm mdworker[1435]: (Warning) Import: Bad path:
10/03/15 3:14:24.080 pm mdworker[1434]: (Warning) Import: Bad path:
10/03/15 3:14:24.081 pm mdworker[1434]: (Warning) Import: Bad path:
10/03/15 3:14:24.082 pm mdworker[1435]: (Warning) Import: Bad path:
10/03/15 3:14:24.085 pm mdworker[1433]: (Warning) Import: Bad path:
10/03/15 3:14:24.085 pm mdworker[1433]: (Warning) Import: Bad path:
10/03/15 3:14:24.179 pm mdworker[1436]: (Warning) Import: Bad path:
10/03/15 3:14:24.180 pm mdworker[1436]: (Warning) Import: Bad path:
10/03/15 3:14:25.132 pm mdworker[1440]: (Warning) Import: Bad path:
10/03/15 3:14:25.133 pm mdworker[1439]: (Warning) Import: Bad path:
10/03/15 3:14:25.134 pm mdworker[1438]: (Warning) Import: Bad path:
10/03/15 3:14:25.135 pm mdworker[1437]: (Warning) Import: Bad path:
10/03/15 3:14:25.138 pm mdworker[1440]: (Warning) Import: Bad path:
10/03/15 3:14:25.141 pm mdworker[1439]: (Warning) Import: Bad path:
10/03/15 3:14:25.144 pm mdworker[1438]: (Warning) Import: Bad path:
10/03/15 3:14:25.146 pm mdworker[1437]: (Warning) Import: Bad path:
I think it's due to my external drive and something in the .fseventsd/ folder.
Restarting fixes it often maybe.