Mac scanning problem solved

Stephen Withers
Thursday, 05 May 2011 13:14

Opinion and Analysis

A scanning software problem with Mac OS X may be caused by devices you're no longer using.

Several months ago, I found I could no longer scan via the network from my trusty Canon MP800R to my 24in iMac running Mac OS X 10.6. I don't scan very often, and I have a couple of other computers that were still working fine in this regard, so I didn't worry too much about it.

Then on Monday I finally got round to upgrading our iMac G5 from 10.4 to 10.5. (That took about six hours, incidentally, including the 10.5.8 update which I already had on a thumb drive and a bunch of others that came via Software Update). After installing the latest Canon drivers and related software, guess what? It wouldn't scan, and the symptoms were exactly the same as on my 24in iMac.

Much head-scratching followed, and a few choice words were uttered.

After trying a few things such as checking the firewall settings, I looked in the logs and found the user diagnostic reports included references to an Epson-related file in /Library/Image Capture/TWAIN Data Sources. I don't have an Epson, but it's quite possible that somewhere along the way I did use an Epson all-in-one with that machines while reviewing the device. And I'd certainly installed Epson and Brother software on the 24in iMac for the same reason, and both were mentioned in the logs.

Opening /Library/Image Capture/TWAIN Data Sources and deleting all the files relating to scanners other than the MP800R did the trick on both iMacs, restoring normal operations.

So what had happened? Please read on.