I just remembered that the project im working on was made in version 4.8.1 and the ones that i have to open at the moment are all from 4.8.0 or earlier.
I also remembered that just before this crash started happening i opened the Epic Games Launcher with a bad internet connection; this caused it to fail during its update check and i think it may have reverted its version number to 4.8.0 for some reason.
Im updating back to 4.8.1 so fingers crossed it works after this.