TCP Frozen Window
When a TCP station communicates with another station, a window value is sent as an indication of the amount of data the sending station is willing to take for the next packet. If the sending station keeps advertizing the same window size, it can indicate that the station is unable to process any addition data at this time. The event is displayed when the percentage of frozen window packets (by application and address pair) is above the critical value set in the Expert Thresholds.
Possible reasons for the event:
The system advertising the frozen window size is too busy to process any more data.
The system advertising the window size TCP/IP stack is misconfigured (only an issue on older systems - modern Windows systems automatically configure enough network buffers to accommodate TCP traffic).
An application is so slow that it can not keep up with the data stream from the network, or is waiting for another event to occur.
A mismatch between sending and receiving station processing ability.