StarCraft 2 relies heavily on temporary CASC (Content Addressable Storage Cache) files. If one of these files is corrupted, the "Preparing Game Data" link fails a checksum test and attempts to re-download the entire index, causing a 10+ minute hang.
Other culprits include corrupted cache folders or Windows security settings blocking the game's ability to save its configuration. Step-by-Step Solutions 1. The Language Sync (Most Effective) starcraft 2 preparing game data link
Here is a guide to the links and libraries necessary to prepare SC2 game data. StarCraft 2 relies heavily on temporary CASC (Content
This solves 70% of "Preparing Game Data" errors. starcraft 2 preparing game data link