Wait for the message: “Microsoft Office rearm successful.”

What to do if you see “Preview Expired” in Office - Help Center

. Preview versions are time-limited and typically enter a read-only mode once expired. 1. Activate with a Valid Product Key

The system was deployed without specifying production volume license keys in the configuration file. Method 1: Convert the Preview via Office Account Settings

If the preview version remains stuck in expired mode, a clean install using the is the most reliable "official" fix:

Below is the definitive guide to diagnosing, fixing, and permanently removing this expiry error.