USB 3.0 to gigabit ethernet keeps crashing system with 10.10.1/2
It may be worth starting up in Safe Boot mode and then using a utility like Onyx to clear your system caches and see if that helps with your stability issues.

Otherwise can you not transfer wirelessly? It won't be as fast as GB Ethernet but it would still get the job done. Failing that I'd suggest either an Apple Thunderbolt to Ethernet adapter, or a USB transfer cable like this (probably much cheaper than the Apple adapter).