I was recently called out to a new client site to stop a Microsoft Outlook 2010 client from crashing every time email was sent or received. It took a while to discover the cause of the problem because the issue was related to a configuration that has not been supported by Microsoft since Exchange Server 5.0 was released in 1997. So, not something I’d expect to find anyone still using.
Don’t Store PST files on a network share
According to Microsoft, among the consequences of using a network share to store pst files are:
When you store .pst files [on a network share], shares may stop responding. This behavior may cause several client-side problems, such as causing Outlook to stop responding or freezing desktops on client computers.
There is some further information and analysis over on the technet blog, including additional problems caused on the server side, from way back in 2007!
Hopefully this information will jog the memory of future troubleshooters or give them another place to look when trying to solve problems with Microsoft Outlook.