Click the link below for more details and to download the hotfix.

http://support.microsoft.com/kb/2902864

When Microsoft rolled out Windows 8.1 on 17th October, there was one annoyance that has popped up regarding Secure Boot, leaving an annoying watermark on the desktop. Many Windows 8.1 users were reporting that they have a watermark stating "SecureBoot isn't configured correctly." Today, Microsoft has rolled out a fix (KB2902864).

"Secure Boot helps increase the security of Windows 8.1 and Windows RT 8.1 PCs by stopping unauthorized software from running. If you see a "SecureBoot isn't configured correctly" message in the lower-right corner of the desktop, it means that Secure Boot has either been turned off or hasn't been set up correctly on your PC," Microsoft explains.

Unfortunately, those who did not want to enable SecureBoot were stuck seeing the watermark. Microsoft today rolled out a hotfix that removes this watermark for those of you on Windows 8.1 and Windows Server 2012 R2. (Source)