Scanning was working fine but not it won't scan. connected directly to via USB cable

SOURCE: pixma mp600r scanning setup

Try turning off the windows firewall.
If that works, then add the Canon scanner app to the list of applications that are allowed through the firewall, then turn the firewall back on again.

SOURCE: When connected to Airport Express via USB, it will

Airport Express provides only a print server, not a networked usb hub so it can only print. I'm afraid you'll have to go back to wired for scanning.

SOURCE: Wireless printing does not work

For an effective wireless connection, the printer should be connected to one of the LAN ports of a configured wireless router. This way, every pc(mostly laptops with wireless capability) can print to the printer. You will need a wireless adapter for desktop pcs to access any resource made available wirelessly ok. Good luck

SOURCE: Canon ImageClass MF6540- works fine for printing,

Need some clarification about the error.
We need to know the exact error.
Generally all the scannars use TWAIN technology which bridges the scanner with WIA(windows imaging aquisition).
We need to know if WIA which is a part of the operating system is working. For diagonasting we can try using teh scanners and camera wizard from control panel or we can use mspaint even.
If WIA is working in that case the problem may be with the registry values of the scanner.
WE can try making a new user account with admin rights and then we can try installing the scanner. We can even try using Revo uninstaller for uninstallation of the scanner because it will remove all the entries from registry, then we can try scanning.
BEST OF LUCK.

SOURCE: I asked for the manual for the scanning function

Hi,

You can download the complete on-screen manual in .EXE format by clicking this link (File size 4.59 MB)

This manual has the detailed steps for scanning.

After downloading, install the manual by double-clicking the "mp150_ug_win_us_100.exe" file or clicking the "Run" button in the download complete dialog.

To view the manual, click the "MP150 On-screen Manual" shortcut icon on your Desktop.

Then select "Scan Guide" from the menu and click "Enter" button. (See attached image)





Hope this solves your problem.

Kindly let me know if you have any difficulty in downloading or viewing the manual.

Thanks for using FixYa.