Evolution local mail format has changed

Support and Help
1

Dear all,

I’m using Ubuntu 25.10 desktop, using Gnome

On January first, 2026, opening evolution on Ubuntu 25.10, I received a message that

Evolution’s local mail format has changed.
Evolution’s local mail format has changed from mbox to Maildir. Your local mail must be migrated to the new format before Evolution can proceed. Do you want to migrate now?

An mbox account will be created to preserve the old mbox folders. You can delete the account after ensuring the data is safely migrated. Please make sure there is enough disk space if you choose to migrate now.

I searched briefly on the Internet but did not find any mention of this migration. Has anyone heard about it ?

Thanks

Alain

2

Hello Alain,

I looked into this a bit. This message is not something new or specific to Ubuntu 25.10.

What you’re seeing happens when Evolution detects old local mail folders stored in the legacy mbox format. Evolution has supported (and preferred) Maildir for local folders for years, and when it encounters existing mbox data, it prompts to migrate.

So in short:

  • This is expected behavior, not a bug.
  • It’s triggered by existing mbox local folders, not by GNOME or Ubuntu itself.
  • Evolution creates a separate mbox account to preserve the old data, which you can remove later after verifying everything migrated correctly.

As usual, it’s a good idea to back up ~/.local/share/evolution/ before proceeding, but the built-in migration is generally safe.

Hope this clarifies things :+1:

1 Like
3

Great, thanks for the explanation.
I’m still a bit surprised that it occurred now, as I did not make any significant change to my system since the last upgrade in early November.
Alain