The scanner worked previously, but it doesn't anymore. So I deinstalled all Canon software, incl. drivers using USBDeview. After restarting the laptop, I started the Canon driver installer mp68-win-9000fmkii-1_00-ejs.exe, then followed the instructions on screen. The last step is connecting the scanner to a USB port and turning it on. Windows then tries to install the driver, but it fails:
I tried with two different USB ports, one USB 2.0 the other one 3.0. Other USB devices work fine with my machine, a ThinkPad T420si. The scanner also works fine, when connected with the same cable to a ThinkPad T550 running Linux.
What I also tried is opening Windows 7's Scanners and Cameras, then selecting Add Device / Have Disk.... I can select CNQ9604.INF
which is included in the package from Canon, but then no scanners are listed:
What can I do? Where do I find log files that tell me what is happening?
In the end I want to scan using VueScan, which I just bought.
Update
As described in another question, I solved the problem by copying usbscan.sys
from C:\Windows\System32
to C:\Windows\inf
and restarting the driver installation process.