Are there a lot of other things in "C:Users/jacks/Downloads"? It may be lagging because it is copying a lot of stuff over. The HTML should be in a folder with only its own assets (if it has any). Otherwise if you have "Copy HTML Folder (assets)" toggled on, it will copy everything from the folder, including all subfolders (your download folder in this case). So put the HTML into a folder of its own with only its assets. If it is only an HTML file with no other assets, you can turn off copy HTML folder.
You can also try removing the spaces from the entry HTML name and replace them with underscores, and remove the brackets (). It should work without that, but it's worth a try.
I hope this helps.