A. By default, when OWA has forms-based authentication enabled, sessions have a 15-minute inactivity timeout for public or shared computers and 24 hours for a private computer. If you're using a public computer to compose a long email message that takes more than 15 minutes to write, the session will time out and you won't be able to send the message. You can change this timeout value (which is the cookie lifetime) by using this procedure:
- Log on to the Exchange server as an Administrator.
- Start the registry editor (regedit.exe).
- Navigate to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeWEB\OWA subkey.
- From the Edit menu, select New - DWORD value.
- Enter a name of PublicClientTimeout and press Enter.
- Double-click the new value and set it to the desired number of minutes before a timeout (1 to 4320), set the type to decimal, and click OK.
- To set the timeout period for a private client, repeat the process of creating a DWORD value, but this time enter a name of TrustedClientTimeout and again set the value to the number of minutes before a timeout (The value for private computers should be significantly higher than for public computers.)
- Stop and restart the World Wide Web (WWW) Publishing service by using these commands at the command line.
net stop w3svc net start w3svc