Ho risolto..
Ho inserito questo codice nello share-config-custom.xml
<blockcode>
<config evaluator="string-compare" condition="RepositoryLibrary" replace="true">
<!–
Root nodeRef or xpath expression for top-level folder.
e.g. alfresco://user/home, /app:company_home/st:sites/cm:site1
If using an xpath expression, ensure it is properly ISO9075 encoded here.
–>
<!– <root-node>alfresco://company/home</root-node> –>
<root-node>/app:company_home/st:sites/cm:miosito</root-node>
<tree>
<!–
Whether the folder Tree component should enumerate child folders or not.
This is a relatively expensive operation, so should be set to "false" for Repositories with broad folder structures.
–>
<evaluate-child-folders>false</evaluate-child-folders>
<!–
Optionally limit the number of folders shown in treeview throughout Share.
–>
<maximum-folder-count>500</maximum-folder-count>
</tree>
</config>
</blockcode>