Sometimes, I can simply restart the Information Store and Exchange will be responsive to outlook and owa clients. (note that the services have status 'started' when viewed in Control Panel).
Sometimes, I have to power cycle the sytem -- it is a Pentium D 3.2GHz with 4G RAM, serving as Mailbox, Hub, and Client Access server.
Will it be running out of Physical memory? We only have 30 users with a storage .edb of 12G and a public folder .edb of 2G. Total memory usage is around 5G (1 G more than RAM).
The only thing running during early mornings (1am -5am) are: Windows Automatic Update (which I just disabled) and Ex ESE online defrag.
Any ideas is appreciated.