See 
http://www.wireshark.org/docs/wsug_html_chunked/ChAdvFollowTCPSection.html
Means that "Follow TCP Stream" keeps only the application layer data 
(i.e. TCP, IP, Ethernet ... data is removed).
So you can NOT :
- save as in a .pcap format.
- reload the file into wireshark
I think you must do :
- conversation filter
- save as   and    select the option "Displayed" inside "Packet range" 
frame.
Olivier
ram singh a écrit :
Hi all,
         i have been using Wireshark for network analysis.But i can't 
view the saved files(saved using Follow TCP Stream) in Wireshark 
window.The error message reads as below:
"flow5.pcap" isn't a capture file in a format Wireshark understands.
Can anybody help me to save the files in proper format and also to 
view that file.
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