So, my girlfriend and I have been in love with this game, long story short, we wanted it to be way more challenging. I found the 7DTD mod launcher and got it installed on both of our computers. The launcher works great on my computer, its a bit confusing, and I cant find out how to load anything other than True Survival, but luckily that's the mod we were mostly interested in. My girlfriends laptop is a different story, when the launcher goes to open the game, we get the 'Unable to connect to steam' error message, I've looked up fixes on google, tried every single one. Nothing has worked, so my last hope is this forum and/or the subreddit. The vanilla game loads up just fine, its only when mods are loaded. I'll also mention that her computer is running Windows 8, not sure if that could cause any issues with the launcher.
I've tried:
Deleting ClientRegistry.blob
Un/Reinstalling Steam
Un/Reinstalling 7DTD
Un/Reinstalling the 7DTD Launcher
Un/Reinstalling the Mods