WinSCP can log session events. Log can be written to file, to log window, or both.

Logging can be enabled from Logging tab, which is present on both Preferences dialog and Login dialog. Use the latter if you want to log authentication process. Logging can also be enabled from command-line.

Events can be logged in two formats:

• Text log: Events are logged in unstructured form with configurable level of verbosity. Information logged differ with protocol used. This format is useful to troubleshoot problems with connection. You should also include this log when reporting bugs or asking for support.
• XML log: Events are logged in structured form in XML format. This format includes less information than text log. However its format is documented and independent from protocol used. You will find this format particularly useful to analyze automatically performed operations, such as when using scripting.

Note that passwords and passphrases not stored to either log format.