Ive found a solution! I use the ultra version but this may work for others, i fixed it by using the C6 Version instead of C7 and it works so enjoy optifine in all its glory!
yup, for me C6 works, but C7 and C8 don't. but then I've another problem, if I use C6 with ChickenChunks I get another crash. I have to remove ChickenChunks to get rid of the crash.
what's also very weird is whenever I use optifine with MultiMC5 I get terrible fps lag. if I remove optifine it's ok, but still not very good enough to play with. so that means I can't use MultiMC5 aswell
I'm really sad to see Optifine going this way, because I'm someone who just can't play without it. I've been hoping for a while that a new mod developer would be willing to make a forge compatible version of optifine, but I guess that's not really happening as it'd probably be quite alot of work.
I know forge does a few things to improve things like fps, but not enough for me to say that I can play without optifine.
also am having alot of problems with Biome's o Plenty and Optifine, I usually end up removing Biome's o Plenty to get rid of terrible FPS lag, which is a shame because I quite like Biome's o Plenty