By default File Channel has an 8kb buffer. If the channel is not used much, it may take a while for the expected entries to appear. The buffer can be removed, this article describes how.
To disable buffering for a File Channel we need to write the following attribute to it:
The attribute can be written through the Support Tab (requires Authorization code from Customer Support) or using SchemaTool.exe and appropriate xml file. The File Channel object attributes should look similar to the following, once the attribute has been added: