Reader Paul Moortgat's Mac appears to be unhappy with a new hard drive. He writes:
I replaced the 500GB internal with a 1TB drive in my Mac Pro. I used SuperDuper to copy the disk. Now each time I create a file or a folder on the Desktop and place it on the hard drive icon or trash an item, I'm asked to enter my password. I reset the PRAM and repaired permissions to no avail. How can I get rid of that authentication dialog box?
This is indeed a permissions issue, but it can't be treated with Disk Utility. And the reason it can't is because Disk Utility's Repair Permissions feature repairs permissions only for files installed by OS X, Software Update, or an Apple software installer. It won't touch your documents, the stuff in your Home folder, or third-party applications.
That said, something definitely got mucked up when you copied your files from your old drive to the new one. What I suggest you do is select one of these files, press Command-I, and in the Sharing & Permissions area of the resulting window, see who "owns" the file. If it's not you but some other entity, there's your problem. If you change the permissions so that you own the file, you won't see the warning.
The broader way to deal with this is locate the folders that contain your files--Documents, for example--do a Get Info on those folders, change permissions so that you're the owner, and then choose Apply to Enclosed Items from the Tools menu at the bottom of the window. That should change the permissions of all the items in the folder to match those you just set.
This story, "Perplexed by Permissions" was originally published by Macworld.