Problems with iMail, looking for replacement suggestions

I don't have a suggestion for a Mail client (when I had a PC I used webmail, and on my Mac I only use Mail) but you might try repairing your hard drive (boot to the Recovery HD by holding Option on restart, then click Disk Utility, click your Macintosh HD and click "repair disk"). Also make sure you've installed all updates and you might also test the issue in Safe Boot (restart holding shift) and see if the problem happens.

If the issue continues to happen, I'd reinstall (won't erase your data).

I know you're ready to give up on Mail, but my fear is that if Mail is broken, something else may be (or may follow) so I'd fix the issue, even if you plan to use something else. Good luck!

If you are having to do that on a weekly basis, you have a serious problem that needs to be addressed. Purplecow's idea to repair the hard drive is a good starting point, as hard drive corruption could explain repeated corruption of the mail indices.

If repairing doesn't help, you may want to consider starting Mail over from the ground up. Quit Mail, then move the following items to the desktop:

~/Library/Mail/

~/Library/Preferences/com.apple.mail.plist

(Note that ~/Library is invisible in Lion, so you have to hold down the option key while selecting Library from the Finder's Go menu to get in there.)

Now restart Mail, and it will be just like the first time you opened it. Set up all your accounts again. If they are IMAP accounts, all your mail and mailboxes should reappear. If they are POP, or if you had some messages stored in "On my Mac" mailboxes, you can import messages from the appropriate mailboxes in the Mail folder on your desktop (using File -> Import Mailboxes). Recreate any rules and signatures.

iMail? It's Mail.

at the time I wasn't looking for a resolution to fixing iMail.

Yes, but I've often found that it's not always the question that's asked that needs to be answered. When a part of the system, such as Mail, stops working properly, it's always best to try to fix it rather than work around it. It may only be the tip of a greater iceberg, waiting for that one destabilizing moment to flip over and dump you in the drink.

I didn't however start from the ground up, so I'll give your approach a try Thomas.

If that doesn't work, let us know and we can try other solutions. Perhaps reinstalling the system, right on top of the old one, which will replace any corrupt system files with clean copies and leave everything else alone.

You are certainly welcome to try Sparrow. However, at this point I think you've got some corruption in your system, and it's anybody's guess how deep that may go. I would recommend reinstalling the system, as I mentioned in my last post.