You could boot Windows in safe mode by using the F8 key during startup. But if you are repairing or troubleshooting Windows, it might require several restarts and that too in Safe Mode. So always using the F8 key while booting for starting in Safe Mode could be quite annoying. So for your convenience, you could always boot Windows in Safe Mode using the boot options.
1. Type ‘ msconfig ‘ in ‘ Run ‘ or in search box and press Enter.
2. In the ‘ System Configuration ‘ window, select the ‘ Boot ‘ tab.
3. Under the ‘ Boot options ‘ section, tick the ‘ Safe boot ‘ checkbox.
4. Click on ‘ Apply ‘.
For switching off automatic safe boot, just untick the ‘ Safe boot ‘ checkbox.