Could not load Libary Client

[Griff]

I'v played the game plenty of times but I don't know if it's to do with spec (Intel Core i5, Nvidia Geforce GT 630M 2GB, 4GB RAM, Windows 8.1 64.BIT)

Plus I do play it on a External Hard Drive for the sake of the Hard Drive Space on my laptop

[Dragriff]

Maybe it's because of the external hard drive? I'unno.
Have you tried the things listed in here? https://support.steampowered.com/kb_article.php?ref=9626-UOAC-4950