Windows 10/8/7 has several watermarks which appear when certain situations warrant it so. One of them is the Test Mode watermark. This watermark may appear in the bottom right part of your Windows desktop, if you install an application whose drivers are not digitally signed by Microsoft and if they are still in the testing phase.
What is Test Mode in Windows
Most are familiar with For testing purposes only, Evaluation copy, Safe Mode, etc watermarks. The Test Mode is not so familiar a watermark, however!
The TESTSIGNING boot configuration option determines whether Windows 7 or Vista will load any type of test-signed kernel-mode code. This option is not set by default, which means test-signed kernel-mode drivers will not load by default on 64-bit versions of Windows Vista and later versions of Windows.
For 64-bit versions of Windows 10/8/77 & Vista the kernel-mode code signing policy requires that all kernel-mode code have a digital signature. However, in most cases, an unsigned driver can be installed and loaded on 32-bit versions of Windows Vista and later versions of Windows, explains MSDN.
The TESTSIGNING boot configuration option is enabled or disabled through the BCDEdit command.
To enable test-signing, use the following BCDEdit command:
Bcdedit.exe -set TESTSIGNING ON
To disable test-signing, use the following BCDEdit command:
Bcdedit.exe -set TESTSIGNING OFF
To use BCDEdit, you must be a member of the Administrators group on the system and run the command from an elevated command prompt. To open an elevated Command Prompt window, create a desktop shortcut to Cmd.exe, right-click the Cmd.exe shortcut, and select Run as administrator
When the BCDEdit option for test-signing is enabled, Windows does the following:
- Displays a watermark with the text “Test Mode” in all four corners of the desktop, to remind users the system has test-signing enabled. However, starting with Windows 7, Windows displays this watermark only in the lower left-hand corner of the desktop.
- The operating system loader and the kernel load drivers that are signed by any certificate. The certificate validation is not required to chain up to a trusted root certification authority. However, each driver image file must have a digital signature.
As mentioned earlier, this water mark may appear if you install an application whose drivers are not digitally singed by MS and they are still in the test phase. You can ofcourse use sigverif command to check if there are any unsigned drivers and to which application/device they are tied with.
Remove Test Mode watermark in Windows
If in the rare eventuality you get to see the Test Mode | Windows 7 | Build 7600 watermark on the bottom right part of your Windows desktop, for reasons unknown to you, you may have to re-enable driver checking first. Open a Command Prompt as an Administrator and enter the following commands:
bcdedit.exe -set loadoptions ENABLE_INTEGRITY_CHECKS
Hit Enter. Now type:
bcdedit.exe -set TESTSIGNING OFF
Alternatively you can also use Microsoft Fix it 50756 from KB2509241 to remove the Test Mode watermark easily.