The page is frozen or not responding.

First, give it a moment — the tools do real work in your browser (building PDFs, rendering 3D covers), and a large manuscript or high-resolution image can take a little time, especially on an older computer. What looks frozen is often just working.

If it's genuinely stuck:

1. Reload the page. Your saved book is stored locally, so reloading won't lose it (any unsaved edit in the last few seconds might need redoing).
2. Close other heavy tabs to free up memory, then try again.
3. Use an up-to-date browser — see Which browsers are supported? — and disable aggressive script-blocking extensions for the site.
4. Try a different browser if one consistently struggles.

If a specific step always freezes (say, formatting a particular manuscript), see My file will not upload or email us — see How do I report a problem without sending my manuscript?