The Save As dialog box appears two times when you try to save a file in Word 2010 or in Word 2007

SYMPTOMS

When you click Save or Save As to save a file in Microsoft Word 2010 or in Microsoft Word 2007, the Save As dialog box appears two times.

CAUSE

This problem occurs because the Normal.dotm template is corrupted.

RESOLUTION

To resolve this problem, create a new Normal.dotm file by changing the name of the old file. To do this, follow these steps: 

1. Start Windows Explorer, type %appdata%\Microsoft\Templates in the address bar, and then press Enter.
   
   
2. Right-click Normal.dotm, and then click Rename.
   
   
   
3. Change the file name to Normal.old.dotm.
   
   
   
4.  Restart Word. A Normal.dotm template is automatically generated.
   
   
   
5. Try to save a file to check whether the problem is resolved.

source: https://support.microsoft.com/en-in/kb/2637570