macOS User Guide
- Welcome
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- Use Continuity across your devices
- Use your iPad as a second display
- Hand off between devices
- Insert photos and scans from iPhone or iPad
- Insert sketches from iPhone or iPad
- Copy and paste between devices
- Use Apple Watch to unlock your Mac and approve requests
- Make and receive phone calls on your Mac
- Control accessories in your home
- Send files between devices with AirDrop
- Use AirPods with your Mac
- Stream content to Apple TV
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- Understand passwords
- Use keychains to store passwords
- Reset your Mac login password
- Set up your Mac to be secure
- Guard your privacy
- Protect your Mac from malware
- Use Sign in with Apple for apps and websites
- Clear your Safari browsing history
- Manage cookies and other website data in Safari
- Find a missing device
- Resources for your Mac
- Resources for your Apple devices
Reset NVRAM or PRAM on Mac
If your Mac doesn’t remember the speaker volume, display resolution or the disk it should be using during startup, you may need to reset your computer’s NVRAM or PRAM.
Note: To print these instructions, press Command-P.
On your Mac, choose Apple menu > Shut Down.
Locate the following keys on the keyboard: Option, Command, P and R. You will need to press and hold these keys simultaneously in step 4.
Turn on your Mac.
Immediately press and hold the Option-Command-P-R keys, before the black screen with the Apple logo appears.
Continue pressing the keys until your Mac restarts; about 15 seconds.
Release the keys.
Resetting NVRAM or PRAM may change some system settings and preferences. You may need to update the speaker volume, display resolution and startup disk preferences in System Preferences.