Many software companies digitally sign their software packages and programs with their digital signature. If this signature is corrupt or invalid, it may indicate that the software was modified illegally and might contain malware. You can disable software with invalid signature to run in Internet Explorer. Here is how :
- Start Internet Explorer browser by double clicking on its Desktop shortcut.
- From the menu bar select Tools → Internet Options.
- In the Internet Options window, select Advanced tab.
- Scroll down and un-check the Allow software to run or install even if the signature is invalid checkbox as shown,
- Click OK to save the settings. Then close the Internet Options window.