Do you know why personal folder files (.PST files) are unsupported over a local area network (LAN) or wide area network (WAN) link?
The .PST files are not meant to be a long-term, continuous-use method of storing messages in an enterprise environment.
Although it is possible to specify a network directory or a Universal Naming Convention (UNC) path as a storage location for a .PST file, network usage is not meant to be a long-term, continuous-use method of storing messages in an enterprise environment.
As you know that a .PST file is a file-access-driven method of message storage. File-access-driven means that the computer uses special file access commands that the operating system provides to read and write data to the file. This is not efficient on WAN or LAN links because WAN/LAN links use network-access-driven methods, commands the operating system provides to send data to or receive from another networked computer.
Other Behaviors of .PST Files over WAN/LAN Links
•All operations take longer.
• Write operations can take approximately four times longer than read operations.
• Outlook has slower performance than the Exchange Client
Suggested alternatives: Can suggest/make use of,
1) .OST files
2) Microsoft Windows Terminal Services
For more information, please refer the following MSDN article.