I am having issues with my Canon MG8250 all-in-one scanner. As you can see, there are visible (and annoying) stains at the center of the image. I cleaned thoroughly the scanner glass and checked the negative (clean) but to no avail. Any suggestion would be much appreciated!
I couldn't see the stains you mention but there are a lot of moire patterns in the scan. If they are there on the scan and not just the up-loaded version, then you need to use then anti-moire facility on the scanner software - I don't know your scanner but mine has an anti-moire option.