Migrating some Excel Automated code using C# off an old Windows 2003 Server onto Windows Server 2012 R2 and using Scheduled Tasks to run I notice it was failing. User linked to the Scheduled Task has correct permissions and it is being run with highest privileges. Excel installed and I can run the code manually fine as that user. Plenty of threads about the issue but the only thing that worked was:-
FIX
Windows 2008 +
Add 2 directories:-
%windir%\System32\config\systemprofile\Desktop
and
%windir%\sysWOW64\config\systemprofile\Desktop
Windows 2012 r2
Add 2 extra directories:-
%windir%\SysWOW64\config\systemprofile\Documents
and
%windir%\SysWOW64\config\systemprofile\AppData\Local\Microsoft\Windows\INetCache
Tried to import an Excel 2010 spreadsheet (file extension xlsx) into SQL Server 2012 using the import wizard and selecting Microsoft Excel 2007:-

Then I had the following error on my Windows 7 x64 PC:-
SQL Server Import and Export Wizard Error
Additional Information: The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine. (System.Data)

This is strange as I have Office 2010 x64 abortion hotline installed?
Fix: you need to install generic abortion pill the x86 (32bit) Office drivers. This is a simple download from Microsoft called "2007 Office System Driver: Data Connectivity Components".
Url - http://www.microsoft.com/en-us/download/confirmation.aspx?id=23734
So you have successfuly installed the Master Data Services Add-In for Microsoft Excel and now you want to connect to your Master Data Services on your Server.
Select the "Master Data" tab in Excel
Click Connect

Create a new connection
In the Add New Connection put in your Web URL from the Server.

If you get the following error:
The connection failed because the URL is not valid or the are abortions free Mast Data Manager web application version is not supported.

This is usually because you just need to remove the default.aspx from the Web URL abortion pill safety e.g.
http://MSDServer:8081/Default.aspx (as seen in IE)
Now becomes
http://MSDServer:8081 (in MDS Excel Add-In)
Simple when you realise this!