This is a primary suspect. A corrupted or incomplete installation will almost certainly produce this error. This can happen if the installation is interrupted, if a previous version of WinCC wasn't properly removed, or if system files become damaged. One user on the Siemens forum succinctly stated that "if you cannot open an existing project or cannot create a new one, you have a corrupted installation of WinCC". This is often the first thing to rule out.
The underlying WINCC SQL instance is stopped, corrupted, or lacks permission. A Basic Application Could Not Be Started Wincc 7.5
Check and set it to Automatic and Start it. 4. Configure SIMATIC Security Controller This is a primary suspect