When you begin typing a file or folder name in Common dialog box (Open / Save As) in an application, the Auto Complete drop-down will appear by default. To prevent the AutoComplete dropdown from appearing, follow these steps.

> Click Start, Run and type REGEDIT and press Enter

> Navigate to the following key:

HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\AutoComplete

> In the right pane, create a new REG_DWORD value named AutoComplete In File Dialog

> Double-click AutoComplete In File Dialog value and set it's value to 0, and then click OK.

> Close Registry Editor