"Failed to load mods: Error while running setup for entity prototype "forcefield-gate-blue" (gate): next_upgrade can't be set when flag 'not upgrade-able' is set."
Can you provide me a mod list that you are playing with? This way I can test if I fixed it. (An empty save file will have all your mods that I can sync to).
In my case it is "walls-block-spitters" and "aai-programmable vehicles"
Removing either of the other two does not fix it. Removing ForceFields does however. Hope this helps.
