You should use available run mode for nosamplecontent , Documentation
Author
java -server -XX:MaxPermSize=256m -Xmx1024M -jar cq5-author-p4502.jar -r author, nosamplecontent
Publish
java -server -XX:MaxPermSize=256m -Xmx1024M -jar cq5-publish-p4503.jar -r publish, nosamplecontent
Another way would be to uninstall sample content package: https://docs.adobe.com/docs/en/cq/5-6-1/deploying/security_checklist.html#Remove Example Content