Extracting isn't the same as installing. You must open the folder, select the font files, right-click, and select "Install for all users."
Check for a "Part 2" or "Mirror" link. Large font collections (especially those with thousands of files) are often split into multiple volumes to stay under server upload limits. font collection download zip fix
If the file size on your disk is significantly smaller than the size listed on the website, the download was likely cut short. Delete the file, clear your browser cache, and try downloading it again using a stable connection. 2. Dealing with "Incomplete" Font Packs Extracting isn't the same as installing