Yesterday I had a big problem with my Canon CanoScan 8800F scanner. I just couldn’t start TWAIN driver in Photoshop or any other program (I tested Paint, and you can obviously see the false inductive conclusion I made). Photoshop/Paint would just start the WIA driver and that was it. I installed all versions of all drivers but without success. But after couple of hours of fruitless agony (I just can’t stand when I can’t fix things) I found the solution on some page (and believe me, I did my homework on google.com).
The solution is simple: there are no problems with the drivers, you only need to install Photoshop Optional Plugins. That solved my problem in Photoshop (Paint can use WIA only as I found out). I probably missed optional plugins check box when installing Photoshop. Or maybe I even unchecked it. I just couldn’t believe that you have option not to install TWAIN support for Photoshop. Adobe installer installs everything and the kitchen sink but this crucial module for 80% of users is left out.
In any case I now know that I won’t have problem installing TWAIN drivers next time round.