During a

zmmailboxmove -a account@domain.tld  -t newserver.domain.tld
i got a disk full on source server on backup partition /opt/zimbra/backup; at last i managed to move account successfully, but i was not able anymore to purge data;

zmmailboxmove -a account@domain.tld -po
Error occurred: system failure: Account account@domain.tld does not have an old mailbox to purge on server sourceserver.domain.tld
At last i moved all the accounts form this server to new server, i configured proxy on oldserver, but still I have here 24 Giga unused and unuseful store data

du -s -h store/
24G     store/
How can I cleanup this 24 giga of unuseful data?