TestCaddy stores an INI file for all users on a workstation in a folder below the Common Documents folder.

The INI file is a text file which stores a few configuration details for the local copy of TestCaddy to read when it starts up. It stores your SQL Server connection details, the last user logged in and the last Product Database you connected to.
TestCaddy also stores a text log file for each user in the same folder. The log files have the username as part of the filename, e.g. TestCaddy_BobS.log.
The INI and Log files are useful to send to Tech Support if you are emailing about an issue.
The files can be found in the following folders:

On Windows XP:
%ALLUSERSPROFILE%\Documents\TestCaddy
(typically C:\Documents and Settings\All Users\Documents\TestCaddy )

On Windows 7 and Vista:
%PUBLIC%\Documents\TestCaddy
(typically C:\Users\Public\Documents\TestCaddy )

TestCaddy ensures that all users (Everyone) has full access to the INI and log files.
It should not be required, but you can edit the INI file with a text editor (best done when TestCaddy is not running). You can also delete the ini file if you want the Configuration Wizard to show when you next start TestCaddy.