• Click Start > Control Panel > Folder Options
• Click the File Types tab.
• Page down until you locate the icon that looks like a folder in the “Extensions” column. It will have the word “(NONE)” after the icon and the “File Types” column will show Folder. Not “File Folder”, but just “Folder”. Select that entry and click the Advanced button. From that window you can set the default action to “explore” (remember click the "Set default" button) and click “OK”. Click “OK” again to close out of the Folder Options.

Now you will see the split view everytime you open Windows Explorer.