Problem solved! olcSyncrepl now reads:

olcSyncrepl: rid=001 provider=ldap://masterldap.example.com:389 bindmethod=simple timeout =0 network-timeout=0 binddn="cn=dsyncuser,dc=example,dc=com" credentials="xxxxxxx " starttls=critical tls_cert="/usr/ssl/certs/examplewildcard.cert" tl s_key="/usr/ssl/certs/examplewildcard.key" tls_cacert="/usr/ ssl/certs/cacert_root.crt" tls_reqcert=demand tls_crlcheck=none filter="(obje ctClass=*)" searchbase="dc=example,dc=com" scope=sub attrs="*,+" schemachecking=of f type=refreshAndPersist retry="5 5 10 +"

so the 'uri=""' string is no longer present, and slapd starts normally after converting. Thanks for the quick fix! Best,

gerard