I am just trying to migrate my mail server from Debian 7 on a pi2 using sendmail, dovecot and squirrel-mail to debian9 on a x86 server using sendmail, dovecot and roundcube.

So waht I have done is tar zcvf the user's home folder and expanded it on the new server.

When I log in with roundcube my inbox is empty but all the old folders are there and have content.

I am assuming I have some config to do to get inbox populated but Im scrathcing my head as to what to look at.

When i use Thunderbird client instead I get the same issue, so am I right in assuming its a Dovecot issue?