I recently moved from one hosting provider to another and did not realize that the emails were on the original. This means I can no longer see my long history of mails that were on the IMAP mailbox on the old hosting, and my only hope is that I have my local .ost file backup that I am hoping might be enough to import into my Outlook. The domain names remain the same, but the DNS records have changed.
How can I get my Outlook to read the ost file for [email protected] (from the old hosting) and import it into the inbox of [email protected] (on the new hosting)?
If you have a homogeneous mail server and can you acquire a recovery dump from the original provider, then restore that dump to a safe area, and then locate the /homedir/mail/<domain>/<email login>/Maildir folder. Copy those dump files into your new-server equivalent.
I believe the folders that the mailbox uses are hidden folders in the Maildir folder - and referenced in the subscriptions file (e.g. my-folder in Outlook will be a folder named Maildir/.my-folder and referenced as my-folder in the subscriptions file). You will need to re-populate the subscriptions file based on what was in the dump vs what is now there (hopefully if you haven't changed the folder structure between the dump and the restore dates then you could just overwrite the subscriptions file with the restored version, otherwise merge them manually I guess).
if you're using dovecot then you need to do the following:
$ find <your Maildir folder> -name 'dovecot*' -exec rm -f {} \;
$ doveadm force-resync -u <email address@domain> '*'
$ systemctl restart dovecot
You should then find your Outlook starts to refill the folders as it re-retrieves all the files.