I use Opera Mail a long time and my email account is huge.
Last week, I decided to delete one of my accounts and during the process Opera Mail crashes.
Every time it try to restart, it crashes again.
"A problem has occurred, forcing Opera to close ..."

And since the first crash, it entered on a loop crashing and asking to restart ...

Anyone can help to recover it.

Thanks in advance.

I agree with you. Find Opera Mail discussions is a hard work.

@burnout426, I followed your tips and all work fine.
Thank you!

My time machine backup is from a month ago (stupid backup, no comments please), may I import files from it to try to recover the last "usable" "omailbase.dat" and any other important Opera Mail file? Which other files are important to recover? Preserving my tags, rules and the messages downloaded until that date and organized with my presets, it can work fine?

You can replace the whole "mail" folder, contacts.adr and "wand.dat" with the month-old backup. When you start Opera back up, it'll just sync the changes. This will only work right with IMAP accounts.
It wouldn't be wise to just restore omailbase.dat unless you have a backup from a few minutes before the crash.

@burnout426, I will try this option. Recover my backup and replace the files/folders you suggested.

May this crash could be caused by the amount of messages?

Highly unlikely.

Have you any guess?

I identified another problem, may be needed to create a new thread, but I will ask here, if no problem. When I start Opera Mail, some tabs I had opened some months ago, appear again. In really, there are 3 tabs that are opened when I start Opera Mail, 2 are received messages and the third one is a new message window. It was happening a long time. Even after closing the tabs and restart Opera Mail the same tabs appear again.

Any advice? Thank you.

Dear burnout426,

Thank you for your help, but I have some questions:

1. If I import (renaming the "mail" folder) the messages from my IMAP server, will I lost all my tags, rules, ...? Is there any backup or export process I can do to preserve these information?

2. My time machine backup is from a month ago (stupid backup, no comments please), may I import files from it to try to recover the last "usable" "omailbase.dat" and any other important Opera Mail file? Which other files are important to recover? Preserving my tags, rules and the messages downloaded until that date and organized with my presets, it can work fine?

3. I have a lot of messages, since 2006, if I will download all from the IMAP server it will take a long time to be done. May this crash could be caused by the amount of messages? I use only 2 accounts on Opera Mail, despite I have more accounts I access with Apple Mail and directly from the browser.

Many thanks again for your advice...

Opera Mail has worked fine for over a year on my Macbook Pro.
Today, suddenly, the messages I clicked over was not displayed. The messages on the tabs, I had opened before, did not appear when clicked on it, a blank (gray) screen without any information was showed.
I tried to restart Opera Mail and the following message appear (the original message was in Portuguese and I translate it to English to show below):
"An error occurred while initializing the Opera Mail.
Failed to open the following file:
/User/juninho-mbp/Library/Application Support/Opera Mail/mail/omailbase.dat

Restart the system and try again. If don't work, recover from a backup source may be required. If this is not possible or does not work, report the error in http://bugs.opera.com/wizard/ and seek the help forums for this problem."

I tried to find the "omailbase.dat" on the path informed and the file did not exist on it.
Tried to restart again and again. After this two restarts Opera Mail open, but my messages disappeared. New messages on server was synchronized, but the old ones do not. I use an IMAP server.

Can anyone help?
Many thanks for your advice...

I had opened an attached file (word file) and edited it. When I "save as" the edited file I had changed the file name, but forget to change the destination folder.
When tried to open the file again using Word, it was not available. I thought I saved it on the Opera Mail Temporary folder.
May I recover it?
How can I find it?

I'm using Mac OSX Yosemite and Opera Mail
Version 1.0
Build 1040
Plataform Mac OS X
System 10.10.3

Please I need help to recover this edited file.

Thank you in advance for any help or clue.

EDITED

After some time looking, I found the temporary folder and recover the file.
The folder is located at: Users/[user]/Library/Caches/Opera Mail/temporary_downloads/