Mail won't recognize my database anymore, yet I see the library is intact

Question

While installing a particular program the install crashed. Since then, mail wants to set me up from scratch like it's the first time running/ opening mail. I see that my user/library/mail database looks all in tact. I can see my accounts in there and lots of mailboxes I've already set up. Seems that the link has to be re-established. I do not want to go through the mail helper installer which would reset the database I think and might erase all my important emails. How do I just run mail and make it see my account and all it's attributes again. ? HELP

Answer 1

Under some circumstances (e.g. lack of available disk space, filesystem corruption, repeated crashes), Mail may discard the current ~/Library/Preferences/com.apple.mail.plist preferences file and create a new one. This file is where all the account settings are stored. As a result, all the non-.Mac account settings are lost. The messages themselves aren’t gone, and messages stored in custom “On My Mac” mailboxes remain accessible, but any messages stored in account mailboxes become inaccessible until you set up the accounts again.
What’s the capacity and space available on the startup disk? Take a look at the comments about disk space in the following article, in case they apply to you:
Problems from insufficient RAM and free hard disk space
Verify/repair the startup disk (not just permissions), as described here:
The Repair functions of Disk Utility: what’s it all about?
After having fixed all the filesystem issues, if any, and ensuring that there’s enough space available on the startup disk (a few GB, plus the space needed to make a backup copy of the Mail folder), quit Mail if it’s running, and make a backup copy of the ~/Library/Mail folder (e.g. by dragging it to the Desktop while holding the Option (Alt) key down), just in case something else goes wrong while trying to solve the problem. This folder is where all your mail is stored.
There are at least three ways to restore the account settings other than using .Mac syncing:
(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 (you may want to quit Mail and trash the new com.apple.mail.plist first to start over). 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 some of the Mail > Preferences settings. 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 try trashing the new com.apple.mail.plist and renaming the old com.apple.mail.plist.saved back to com.apple.mail.plist. Again, be sure Mail isn’t running while doing this. Given the circumstances, there exists the possibility that com.apple.mail.plist.saved became corrupt, but that often is not the case and the settings can usually be restored by just renaming the file back to com.apple.mail.plist.
As a side effect of re-creating com.apple.mail.plist, Mail might rename Outbox (which is where messages waiting to be sent are stored) to Delivered. The name of that mailbox is actually a misnomer, as it would contain messages (if any) that couldn’t be delivered for some reason. You can delete that mailbox if you wish.
Note: For those not familiarized with the ~/ notation, it refers to the user’s home folder. That is, ~/Library is the Library folder within the user’s home folder, i.e. /Users/username/Library.