Importaddress taking a long time to run / does not work
Use Bitcoin Core 0.14 (or higher) and the new importmulti RPC call.

importaddress does always a complete rescan (back to the genesis block) which can take serval hours. Very inefficient if you import multiple addresses.

where importmulti can import multiple keys/addresses at once only requiring a single rescan.
You can also set the according address birthday timestamp to avoid rescanning the complete chain from the genesis block.