Update Microsoft has released a fix: https://support.microsoft.com/en-us/kb/3181507

Microsoft has recently released a security update that prevents Excel opening files downloaded from the internet. If you have received this update it can prevent you opening Excel reports downloaded from Vuture.

The symptoms of this issue are that when you try to open a Vuture-generated Excel file, the file does not open and there is no warning message.

Use the following workaround for this issue until a permanent resolution can be found (this issue is affecting many online services that generate Excel files):

Unblock access to the downloaded file

You need to do this for each downloaded file:

- Right click on the file and select "Properties"

- On the "General" tab click the"Unblock" button

- Click "OK"

You will then be able to open the file as normal.

NOTE – when you save the export report, be sure to switch it to an Excel format – it is defaulted to HTML and then won’t open correctly. 

This is the Microsoft Update that has caused the issue: https://support.microsoft.com/en-us/kb/3170008

Here is Microsoft's note about the issue https://support.office.com/en-us/article/Fixes-or-workarounds-for-recent-issues-in-Excel-for-Windows-49d932ce-0240-49cf-94df-1587d9d97093?ui=en-US&rs=en-US&ad=US - see the section: "HTML files with .XLS not opening outside protected view in Excel 2010, 2013, and 2016 [WORKAROUND]"