A number of users have experienced the following error when attempting to start WYSIWYG R39: Sentinel LDK Protection System: Sentinel key not found (H0007) To fix this problem: Click the Windows Start menu, type services.msc and press <enter>. [The Services console appears.] Ensure that the Services are sorted by name and scroll down to the S section. Four Sentinel services are listed here, and there is a good chance that the one called Sentinel LDK License Manager** is not running (but the other three are). [You can see this in the Status column.]** Right-click on the one that is not running and select Start from the menu that appears. Wait for the Status to change to Running. If necessary, repeat steps 4 and 5 for any of the other services which are also not running. Now R39 should start without problems. ** If you do not see the Sentinel LDK License Manager service in the Services console, it was probably blocked from being installed together with WYSIWYG by your anti-virus software or some other system protection utility (such as Windows Defender), so you have to install it manually, as follows: Copy the following text, complete with the quotes: cd “C:\Program Files (x86)\CAST Software\WYSIWYG Release 39\Bin\Sentinel” Click the Windows Start menu and type cmd Do not press <enter>. [A Command Prompt entry appears at the top of the menu.] Right-click on Command Prompt and select Run As Administrator. Accept the security warning. [The Command Prompt window appears.] Right-click to paste the text copied in step 1. (above here), then press <enter>. Type haspdinst.exe –i and press <enter>. [Your anti-virus or other system protection utility may attempt to block the installation. Ensure that this doesn’t happen either by getting the utility to allow the installation to proceed, or by turning it off altogether.] Wait for the command to complete, and click OK to close the “success” message that appears once it’s done. Restart your computer. Back on the desktop, run R39. If the same error appears, perform the first set of steps above (1 through 6) and then run R39. Should you continue experience problems with this, please contact our technical support department for further assistance.