Hi @Chucker,
Thank you for your query.
I understand that you have installed Windows 10 preview and you are unable to download an upgrade for your printer.
With Windows 10 being a preview and not the final product, you can expect issues to pop up as the preview build changes from one to an updated version. Each new build often resolves some issues, but others may occur. This is part of the normal development process.
Please read this post by @Bill_F Welcome to the HP Windows® 10 Technical Preview discussion board.
You should find it very informative and provides some links for you.
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Good Luck!
Sparkles1