1. Go to WinSCP Preferences.
2. Other General options - Preferences.
3. Click on Storage
4. Make sure radio button of Configuration setting is set to INI file (WinSCP.ini)
5. Save and close WinSCP
6. Go to WinSCP installation directory and search for "WinSCP.ini"
7. Copy INI file to new computer where you want to import the previously stored sessions.
As documented here:
you can export settings to an INI file without changing your configuration.