I had the exact same issue on my Mac, Beelzerob. In the VAB, all equipment was sitting unorganised in the left panel, I couldn't filter/browse through it, clicking an item would spawn it on the ground and I was unable to move it. Like you, I started playing KSP on desktop and wanted to continue on Macbook by copying mods and saves over from my desktop. For me, that was the cause of the issue. Instead of redownloading the mods I copied them from my desktop, assuming that they'd be the same files. I fixed the issue uninstalling all the mods, and redownloading them all for a clean install. The next time I booted KSP it was actually 'installing' the mods and this time they worked. I assume the mods config files change after installing in a way that you can't just copy them from another installation.
