We cannot save router config files and getting below error.
Dynamips error : 206-unable to extract config of VM
configuration directory is not defined in some reason.
1. Click "Import/Export Startup configs" icon on the menu.
2. From "Config" window, choose "Extracting to a directory"
3. From "Directory to write startup-configs", create new folder and click "choose"
4. Now, everytime click "Save" icon, all router’s configuration will be saved.