Date format changes to slashes when exporting xlsx to sharepoint

[delucaja]

Hello All,

I use Excel 2010. On all of my spreadsheets I use the following date format: dd-MMM-yy

Whenever I post a spreadsheet to SharePoint or even if I include a spreadsheet as an attachment in an Outlook email, the viewer "sees" all of my dates with slashes instead of dashes. e.g. 10-Nov-15 appears as 10/Nov/15

In my Control Panel, under Region and Language, the Short date is set up as: dd-MMM-yy

Any idea as to why this occurs?

Thank you,
John