By default the VMware vSphere 5.5 Web Client session timeout is set to 30 minutes. To change this setting so the client never times-out complete the following on the server hosting the Web Client service.
- Open the webclient.properties file in the C:\ProgramData\VMware\vSphere Web Client folder.
- Change the session timeout entry so it reads session.timeout = 0
- Save and close the webclient.properties file.
- Restart the vSphere Web Client service.