If you want to completely close down Skype after logging out, look closely at the notification area on the Windows taskbar. If you see Skype running there even though you exited, right-click the icon and choose Close Skype.You can prevent this from happening in the future by editing an option in the General area of the program's settings.

Use the setting in the log out or restart dialog
When you log out of your Mac or restart it, deselect ”Reopen windows when logging back in” when prompted.
Or start up in safe mode, then restart normally. This doesn't change the setting, but your Mac forgets any windows that were open the last time you logged out or restarted.
If you deselect this setting and an app continues to open automatically:
- The app might be a login item. You can add or remove login items in Users & Groups preferences.
- The app might have installed its own startup software. Often this is controlled by a setting within the app. Check the app's preferences or documentation, or contact the app's developer.
Use the setting in General preferences
To prevent apps from remembering the windows they had open, choose Apple menu > System Preferences, click General, then select ”Close windows when quitting an app.”
Or press and hold the Shift key while opening an app. This doesn't change the setting, but the app forgets any windows that were open the last time you quit the app.
Prevent App From Loading At Startup On Mac Download
If these steps don't work for an app, the app might have its own setting for reopening windows. Check the app's preferences or documentation, or contact the app's developer.
Available only on Mac computers that have the Apple T2 Security Chip, Startup Security Utility offers three features to help secure your Mac against unauthorized access: Firmware password protection, Secure Boot, and External Boot.
To open Startup Security Utility:
- Turn on your Mac, then press and hold Command (⌘)-R immediately after you see the Apple logo. Your Mac starts up from macOS Recovery.
- When you see the macOS Utilities window, choose Utilities > Startup Security Utility from the menu bar.
- When you're asked to authenticate, click Enter macOS Password, then choose an administrator account and enter its password.
Firmware password protection
Use a firmware password to prevent anyone who doesn't have the password from starting up from a disk other than your designated startup disk. To set a firmware password, click Turn On Firmware Password, then follow the onscreen instructions. Learn more about firmware passwords.
You can also use External Boot to prevent even those who know the firmware password from starting up from external media.
Secure Boot
Use this feature to make sure that your Mac starts up only from a legitimate, trusted operating system. Learn more about Secure Boot.
External Boot
Prevent Apps From Opening On Startup Mac
Use this feature to control whether your Mac can start up from an external hard drive, thumb drive, or other external media. The default and most secure setting is ”Disallow booting from external media.” When this setting is selected, your Mac can't be made to start up from any external media:
- Startup Disk preferences displays a message that your security settings do not allow this Mac to use an external startup disk.
- Startup Manager allows you to select an external startup disk, but doing so causes your Mac to restart to a message that your security settings do not allow this Mac to use an external startup disk. You'll then have the option to restart from your current startup disk or select another startup disk.
To allow your Mac to use an external startup disk:
Startup Apps Mac Os
- Open Startup Security Utility.
- Select ”Allow booting from external media.”
Your Mac doesn't support booting from network volumes, whether or not you allow booting from external media. - If you want to select an external startup disk before restarting your Mac, quit Startup Security Utility, then choose Apple menu > Startup Disk.