When you open a Microsoft Office Visio 2007 or a Microsoft Office Visio 2003 drawing that is saved as a Scalable Vector Graphics (.svg) file, only part of the drawing is saved.
This issue occurs if part of the drawing is selected when you save the drawing as a .svg file.
To work around this issue, cancel the selection for all the parts of your drawing before you save your drawing as a .svg file. To do this, click a blank area of the drawing or press the ESC key.
To save your Office Visio drawing as a .svg file, click Save As on the File menu, and then change the Save as type box to Scalable Vector Graphics (.svg).
This behavior is by design.
This issue occurs exactly as it does for other Save As file formats, such as the Windows Metafile Format (WMF), the Enhanced Metafile Format (EMF), the Graphics Interchange Format (GIF), and others. If parts of the drawing are selected, only the selection set is saved. If no parts of the drawing are selected, the whole page is saved.
To export all the parts of a drawing on a page, display the page that you want to export.
To export specific parts of a drawing, select the parts of a drawing that you want to export. To do this, hold down the SHIFT key while you click all the parts of the drawing that you want to export.