On Canon's support page for the 8800F scanner, there are downloads for the Navigator and the driver and menu. However, downloading those on W-11 and installing them just gives a message that the driver needs to be installed. So, the installer is apparently not registering the software items so that they work together.
I have one computer that was upgraded from W-7 to W-10 and then to W-11 (all pro versions of the OS). And the scanner software continued to work just fine with MP Navigator.
However, I no longer have the original install media (CD-ROM). So, I ran the following search in the browser:
"install disc for canoscan 8800f"
Thinking I might be able to find a used original install disc. However, what I found about 4 or 5 items down in the results was an entry for an archive page with the 8800F install cd-rom. I am being careful here not to include a website address although it is an org domain, so not a competing commercial site. In any case, you will have to do the search for yourself so that this post is in compliance with the policies of the community.
On that page, there was an iso of the original installation disc. I downloaded that on a newly configured Windows 11 Pro computer and the software installed just fine and works fine to scan images and pdfs. As many of you know, you don't have to burn the iso to a disc. You simply have to right click in File Explorer and mount it. Then you can run the installer .exe just as if it were already in the download folder. The iso is 399 MB which is consistent with a CD disc capacity (full image).
Caveat, I had first already downloaded the Navigator and driver from the Canon Support site. However, when the installer found those, it simply canceled the install for those "newer" items but continued on and installed the rest of the software. After a restart, I tested the scanner with the newly installed software and it works as before.
I also gave feedback on one of the Canon pages that they could improve their support by making the original ISO available. So, maybe this will help someone who has this issue... Hopefully Canon won't jump in and disable this workaround as the original installed software appears to be forward compatible with later versions of Windows Pro.
