I'm using MS Office 2010. Whenever, I export a dataset to Excel, the date exports in a numerical format instead of the date format. It look perfect in the grid before exporting. Oddly, even if I format the date in Toad to be a Varchar instead of a date, it still exports as a number, which includes decimals if there is also a time value.
Make sure all your Microsoft updates have been run. This issue has been fixed by running updates, but we have not been able to pinpoint the exact one that fixes the issue.
If you have a link on the Check for Updates window that asks if you want to check for updates on Office products, click that and run those updates as well.
A workaround for this issue is to export to Excel File, instead of exporting to an Excel Instance. The issue only seems to occur when exporting to an instance.