Something about my mail folder is crashing Opera

Opera 11.52 on Kubuntu 10.04 was working fine until I tried to start it yesterday. It would come up then crash after about 20 seconds. It would offer to send a bug report and restart Opera. Then after another 20 seconds it would crash again. After the third restart the whole thing would hang with Opera being unresponsive and with Opera using almost 100% of my CPU time. I could only get out by going to a shell and doing a shutdown. I upgraded to Kubuntu 11.04 with no change. I then upgraded to 11.10 again with no change. I uninstalled Opera and then reinstalled it with no change. I read that some people were have startup crash issues so I installed the 12.00 Alpha Build 1116 version and it worked fine at first. I brought over my bookmarks, speed dial settings, and wand data and it was still not crashing. Then I copied my mail forder over to the new installation and then it started crashing just like the 11.52 installation. So, something has been corrupted in my email folder. How can I figure out what it is and/or how to fix it? Is there any way to recover all my stored emails without being able to get Opera to run?

Oh, you can get Opera to run ... you could move your emails and then import them. But in importing them you'd lose all the pror indexing - including which mails were sent and which received.

If you decide to go that route, make sure you recreate your mail account(s) first, then import messages into the (appropriate) account. (If you have more than one account, you'll have to look at a message from each account to decide which account is which.)

I imported from my old mail accounts into Opera 12.00. As the mail was importing, the blue progress bar stopped part way but it said it was finished. I ended up with some duplicate accounts and may have lost some emails. Some emails showed up but had lost their bodies. I spent a lot of time cleaning up and recreating my filters/labels. There seems to be problems in 12 because the filters were pulling in things that weren't related at all. Anyway, after getting it all back to normal, I renamed my mail folder under the 11.52 installation, started it up, and then re-imported my mail from the 12.00 installation. Now I have again recreated my message filters and all seems to be fine. Opera 12.00 is too unstable for me right now so I will revert to 11.52 since it is now working and I am not having any crashing issues. Is there any way to consolidate mail accounts? I have ones with the original names and then I have new ones called "name (2)". I would like to get all the emails back into the original accounts. If I just try to delete the secondary accounts, it warns me that all the email associated with that account will also be deleted. I'd like to somehow change all those emails that are in account "name (2)" back to the account "name" and then get rid of the "name (2)" account.

Only by exporting them from the new account and importing them into the old ...

Yes, thanks, that worked and I am now back in business. I think I ended up loosing some emails but, fortunately, I was in the process of migrating to this computer and the emails are still on my older computer. I guess I could export them from that computer and import them to this one.