Third-party antivirus software (McAfee, Norton, Avast) hates Blizzard’s CASC file structure. Specifically, the "Preparing game data verified" step involves the rapid creation and deletion of temporary .temp and .idx files. Antivirus heuristics often flag this as ransomware behavior and locks the folder.
A common bug where the Battle.net launcher and the in-game settings are set to different languages, forcing a small re-download every time. Blizzard Forums How to Fix a Persistent "Preparing" Window starcraft 2 preparing game data verified
: Right-click your Battle.net shortcut and select Run as Administrator to ensure the launcher has the permissions required to finalize the data preparation. A common bug where the Battle
: Use the Blizzard Support recommended tool: Open the Battle.net Desktop App. This is — it’s a normal part of
This is — it’s a normal part of SC2’s file-checking routine. The game or Blizzard Battle.net client is: