All settings lost on Mail and Safari

Question

I walked away from my computer for about 10 minutes, and when I came back to check my email, I found that all my account settings were reset, and all my bookmarks, etc. gone in Safari. Any ideas why this would happpen? I am in New England with this big storm going on, would that have anything to do with it?

Answer 1

Not sure what the situation is now. Is your mail really gone from ~/Library/Mail/? Hasn’t it “reappeared” there, just like some of your settings?
The only thing that’s usually necessary in cases such as yours, after having fixed all the filesystem issues, is to re-create or restore com.apple.mail.plist using one of the following procedures:
(1) Restore ~/Library/Preferences/com.apple.mail.plist from a backup if you have one. Mail shouldn’t be running while you do this.
(2) Set up your mail accounts again. If given the option to import existing mailboxes or something like that, don’t. Just enter the account information and Mail will automagically rediscover the data in ~/Library/Mail/ when done. You’ll also have to re-configure most of your settings in Mail > Preferences. For spam-related security reasons, the first thing you should do is go to Preferences > Viewing and disable Display remote images in HTML messages if it’s enabled.
(3) Mail may have renamed the old preferences file to com.apple.mail.plist.saved. If that’s the case, you may trash the new com.apple.mail.plist and rename the old com.apple.mail.plist.saved back to com.apple.mail.plist. Again, be sure Mail isn’t running while doing this. Since Mail decided to discard it, I would expect this file to be corrupt (I don’t understand why would Mail discard it and create a new one otherwise), but apparently that often is not the case and the settings can indeed be restored by just renaming the file.
If your mail is gone from ~/Library/Mail/, however (something I find hard to believe, as you apparently didn’t have serious filesystem issues), and it’s not on the server, then you’ll have to either restore it from a backup or try to salvage as many deleted *.emlx files as possible with a data recovery tool such as Data Rescue II, TechTool Pro, or FileSalvage. Of these, the only one I know for sure that can currently recover deleted *.emlx files is FileSalvage. Stop using your computer right now if you want to try that, as anything you do with the computer may cause the deleted files to be overwritten.
Note: For those not familiarized with the ~/ notation, it refers to the user’s home folder, i.e. ~/Library is the Library folder within the user’s home folder.