Session_write_close(): Failed to write session data (user) in PHP7

After the correct installation. I got this message: “session_write_close (): Error writing session data (user). Check that the current configuration of session.save_path is correct (/ var / lib / php / sessions) on …”

This problem gives in the version of omeka 2.3.1 and php7

¿How I can resolved this problem without changed version of omeka y php?

This is an error message that’s resolved in Omeka 2.4. I know you asked about not changing versions but that’s really the simplest answer: upgrade to 2.4.1.