Error message says error writing Mail preferences

Question

There’s a discussion about the very same problem I’m having at <http://discussions.apple.com/thread.jspa?messageID=2047886&#2047886> about Mail not being able to save preferences... or at least a message pops up each time despite the fact that the preferences are saved. Annoying, really. I’ve followed all the steps suggested in the above thread, including terminal commands and repairing of permissions. However, the problem didn’t go away. Unfortunately, the thread above was closed (without being answered), so I had to open a new post. Here’s a description of the problem as stated in the above thread... and the problem occurs exactly like that on my Powerbook running 10.4.7.
**** Original question follows ***
At some point in time, I suddenly began having the problem of every time I close my Mail preferences window, I get an error message stating, "Error Saving Preferences - Writing your preferences to disk has failed. Your preferences may not have been saved. The permissions on ~/Library/Preferences may be wrong or your disk may be full."
My hard disk has many GB free, and I still keep getting the error message after repairing permissions.
I ran a test of changing a couple of prefs, then quitting Mail and relaunching, and my changes stuck.
But some prefs such as changes to signatures won't stick (although they never did, so the latter may be unrelated to my current problem).
In any event, it's disconcerting that I keep getting the error message.
Anyone know what's up? Is there a fix?

Answer 1

The preference file may be corrupt.
Try the following:
Quit the Mail.app first and using the Finder, go to Home > Library > Mail. Copy the Mail folder and place the copy on the Desktop for backup purposes.
Using the Finder, go to Home > Library > Preferences > com.apple.mail.plist. Move the com.apple.mail.plist file to the Desktop.
Note: Moving the com.apple.mail.plist file out of the Preferences folder will require re-entering all email account information when re-launching Mail.
The only exception to this is if you have a .Mac account and/or you created an email account as part of the original computer setup assistant used when first turning on the computer after it was purchased which will be re-created automatically.
Launch Mail and decline the prompt to import mailboxes. After re-entering all email account information, the Mail.app should rediscover the existing account named folders and mailbox files at Home > Library > Mail.
After confirming all mailboxes were successfully rediscovered, you can delete the copy of the Mail folder and old com.apple.mail.plist file from the Desktop.
Test if this resolves the problem.
My hard disk has many GB free, and I still keep getting the error
message after repairing permissions.
What is your hard drive capacity and available free space?