On the mart server host machine,
1. Shut down the mart server.
2. Locate the file web.xml in the folder:
C:\Program Files\erwin\Mart Server r9\Tomcat64\conf\web.xml
(Copy and paste it to back it up first).
Then edit web.xml using notepad or WordPad.
3. In the file, now look for this code:
-<session-config>
<session-timeout>5</session-timeout>
</session-config>
And change the "5" with the desired time in MINUTES. Currently, you should the default of 5 minutes.
Example, if you want to make it 4 hours, it should be like this:
<session-timeout>240</session-timeout>
4. Save the changes.
5. Restart the mart server