This happened to me with an old multifunction printer, a Canon Pixma MP750 (that after about 10 years still works perfectly).
After upgrading to Windows 10, the printer worked but the scanner wasn't usable anymore, with the usual yellow alert sign on device manager. Canon website clearly state the for that and other older models there's no Win 10 support, but the Win 7/8 drivers should/could works, with some limitations/problems not better specified.
Searching online was of no help, due to the sheer magnitude of results pointing to fake/spam sites with just walls of words about drivers/printers/scanners/problems - you know them.
Turned out that the old Win 7 drivers were fine, just not signed, so Win 10 refused to use them.
It's just a matter of temporarily disabling the drivers signing verification, and reapplying the old drivers.
The same thing can probably happens with some other piece of hardware.