Mek and all of its modules work fine without IC2 installed, and IC2 works fine without Mek installed, but when loaded together, I am getting this crash:
http://openeye.openmods.info/crashes/090833d0a1aaf482fa6f2fc961a2b00d
Using latest version of Mek, about to hop over to the IC2 site to check on any known issues over there. Thanks in advance!

That's our issue, I'll take a look in a minute.

@unpairedbracket, any news on this?

Having an issue as well, no crash just 100%+ CPU load if i have ic2 and mek at the same time. Was running java7u65 updated to java8u11 and it seems to be running fine client side. So i updated the java on the server and it still persists. Not sure how I can help if its not throwing me a crash log.

@talentedtoenail The version of IC2 you're using appears to not have @API annotations for the IC2 API, which is causing IC2 stuff to be stripped from Mekanism when it shouldn't be. If you're still getting this, could you post an fml-client-latest.log so I can check that's what's happening? I just looked at IC2 464 (which is what OpenEye says you're using) and it is indeed missing this. Updating to a later IC2 build (466 or later) should fix this.

Updating IC2 worked. Closing topic, thanks guys 👍