You might have run into an occasion when doing a capture from the UI that you are unable to save your capture. You might receive a message like "Not enough storage is available to process this command". The UI tends eat up a lot of resources as it saves conversation information and builds the conversation tree. This is why we recommend you use NMCap, the command line capture utility included with Network Monitor, if you are going to capture a considerable amount of data. But if you do get into this situation, there might be a way to save the trace using the Frame Buffer Manager.
Frame Buffer Manager is a tool in Network Monitor that allows you to select frames in any order and from multiple capture files and add them to a new capture file. You can sometimes use this feature to get around this problem. Just follow these steps:
The file will now be saved. If the capture size is larger than 20megs, then it will be split into multiple files labeled, for instance, out.cap, out(1).cap, out(2).cap and so on. You can stitch these back together using NMCap. Please refer to this blog on stitching chained captures back together.
First, use NMCap if you need to capture for long periods of time. Second, if you do happen to find yourself in this situation with the UI, Frame Buffer Manager can possibly provide a way to save your data.
For version NM3.3 use following step instead of 6. and 7.: Right click frames, choose Add Selected Frames -> Frame Buffer manager