Here’s a tip that comes from a reader, in response to an issue that came up in a previous Mac Help.

“I immediately recognised an issue I have had myself,” wrote Anders Neilsen. “But the answer from Macworld was not what I had expected.”

The issue in question was an error code of -36, generated when copying files from one drive to another. For Anders, the problem began when he upgraded from OS X 10.6 to 10.6.1

“I have a NAS drive, and suddenly I could not copy anything to the drive. I had to live with this for a few months, while Apple tried to fix the problems. Unfortunately, OS X 10.6.2 and other minor updates did not completely correct the problem for me. It was a firmware update from Synology that ended up fixing the last of the Code -36 errors. It seems the OS X 10.6.3 update has also made changes to help some people.”

So, there’s a troubleshooting workflow to solve the problem. First, make sure all the drivers and firmware for your external drive or NAS are up to date. Then ensure you have the latest Snow Leopard upgrade applied before looking for more radical solutions.