Every time I try to run SkyFactory3 I get an error that the immersive engineering model, ieScaffolding, is missing and it just sits there trying to launch the game but it never does. I tried re-installing, switching out the immersive engineering .jar and nothing works.
It looks like he's using the best launcher ever, the MyM Launcher so you can just right click Hard Force Update from it. like magic!
I had already done the hard force update and the same thing happened. Just did it again to make sure and it's still having the same issue.
Right click the modpack in the launcher and click view folder, then click this button twice: Select the "FTB-SkyFactory3" folder and delete it. Close the launcher and then re-open it, then try to install and launch the modpack from scratch. If that still doesn't fix it, then try using curse launcher instead.