1. On the right side, click on the pop-up settings bar;

2. Click on Change Computer Configuration;

3. In Computer Settings, click on General, then Click Restart Now;

4. After restarting, click Troubleshooting;

5. Click Update Options;

6. Click System Startup Settings;

7. Click Restart;

8. After restarting, select item 7 to disable digital signatures.

The above is all about disabling digital signatures in win8 system. Users who need it can set it up manually.