So, ich habe jetzt eine LÖSUNG gefunden, bei der die Mails erhalten bleiben!!!!!!
Auf der englischen Apple Seite ist ein Forum, in dem dieses Problem beschrieben wird. Einer hat ein Script namens mboxbreaker, mit dem man die Mailbox splitten kann. Er schrieb mir folgendes:
"The recommended mailbox size limit for Jaguar or Panther Mail is 1 GB and for Tiger Mail, 2 GB.
An "overstuffed" mailbox issue can occur at any mailbox size but is more likely to occur depending on the number and size of message attachments contained in the mailbox and especially as a mailbox approaches or exceeds 1GB in size for Jaguar or Panther Mail.
This is for Jaguar or Panther Mail only.
This is not my script. I downloaded it from the script writer's website which is no longer available.
Before targeting a mailbox or .mbox file, quit Mail first and using the Finder, go to Home > Library > Mail > this account named folder (named by the user name and incoming mail server for the account) > INBOX.mbox or Sent Messages.mbox - whichever mailbox is affected and move the targeted .mbox file to the Desktop.
When re-launching Mail, a new (and empty) INBOX.mbox or Sent Messages.mbox (whichever is targeted) will be created automatically by Mail within the account named folder when the function is used by the account.
Copy the .mbox file moved to the Desktop and place the copy in another location of your choosing such as your Documents folder for backup purposes before using the script on the original mailbox.
The script is easy to use - just follow the prompts. You are prompted for the number of messages to place in each split mailbox and I believe the default is 200 messages so leave at the default or choose a smaller or larger number of messages if you want to split the mailbox into smaller or larger sections. This will take some time so be patient.
If this script is successful, you can place the split mbox files in the Mailboxes folder at Home > Library > Mail > Mailboxes with the Mail.app quit before doing so. When re-launching Mail, the split mailboxes will be available under On My Mac in the mailboxes drawer if you have a .Mac or IMAP type account or below Trash or Junk (if Junk Mail is set to automatic)."
Es funktionier ganz einfach und falls eine Datei noch immer zu groß ist, kann man die Prozedur mit dieser Datei nochmal machen.
Damit das nicht nochmal passiert schickte er mir auch diesen Link:
http://docs.info.apple.com/article.html?artnum=25812
Hope this helps!
silberfisch