Feb 26, 2020 The color green shows times when the Mac was getting power from a power adapter. As energy use increases, the length of time that a Mac can operate on battery power decreases. If the battery life of your portable Mac is shorter than usual, you can use the Avg Energy Impact column to find apps that have been using the most energy recently. Jun 16, 2020 If you're using one of these computers with OS X Mavericks or later,. you can install macOS Catalina.Your Mac also needs at least 4GB of memory and 12.5GB of available storage space, or up to 18.5GB of storage space when upgrading from OS X Yosemite or earlier. MacBook introduced in 2015 or later MacBook Air introduced in 2012 or later MacBook Pro introduced in 2012 or later.
If OS X Yosemite came preinstalled on your new Mac, you’ll probably never need this article. In this article, you discover all you need to know to install or reinstall OS X, if you should have to.
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If you’re thinking about reinstalling because something has gone wrong with your Mac, know that an OS X reinstallation should be your last resort. If nothing else fixes your Mac, reinstalling OS X could well be your final option before invasive surgery (that is, trundling your Mac to a repair shop).
You don’t want to reinstall OS X if something easier can correct the problem. So if you have to do a reinstallation, realize that this is more or less your last hope (this side of the dreaded screwdriver, anyway).
Reinstalling is a hassle because although you won’t lose the contents of your Home folder, applications you’ve installed, or the stuff in your Documents folder (unless something goes horribly wrong or you have to reformat your hard drive), you might lose the settings for some System Preferences, which means you’ll have to manually reconfigure those panes after you reinstall. And you might have to reinstall drivers for third-party hardware such as mice, keyboards, printers, tablets, and the like. Finally, you might have to reregister or reinstall some of your software.
It’s not the end of the world, but it’s almost always inconvenient. That said, reinstalling OS X almost always corrects all but the most horrifying and malignant of problems. The process in Yosemite is (compared with root-canal work, income taxes, or previous versions of OS X) relatively painless.
How to install (or reinstall) OS X
In theory, you should have to install Yosemite only once, or never if your Mac came with Yosemite preinstalled. And in a perfect world, that would be the case. But you might find occasion to install, reinstall, or use it to upgrade, such as
If your Mac is currently running any version of OS X except Yosemite
If you have a catastrophic hard-drive crash that requires you to initialize (format) or replace your boot drive
If you buy an external hard drive and want it to be capable of being your Mac’s startup disk (that is, a bootable disk)
If you replace your internal hard drive with a larger, faster, or solid state drive
If any essential OS X files become damaged or corrupted or are deleted or renamed
The following instructions do triple duty: Of course they’re what you do to install OS X for the first time on a Mac or a freshly formatted hard or solid-state disk. But they’re also what you do if something really bad happens to the copy of OS X that you boot your Mac from, or if the version of OS X on your Mac is earlier than 10.10 Yosemite. In other words, these instructions describe the process for installing, reinstalling, or upgrading OS X Yosemite.
If you’ve never had Yosemite on this Mac, the first thing to do is visit the Mac App Store, download Yosemite, and install it. Once you’ve done that, here’s how to install, reinstall, or upgrade Yosemite, step by step:
Boot from your Recovery HD partition by restarting your Mac while holding down the Command+R keys.
The OS X Utilities window appears. Select Reinstall OS X, and click Continue. The OS X Yosemite splash screen appears. Click Continue.
A sheet appears informing you that your computer’s eligibility needs to be verified by Apple. Click Continue to begin the process of installing or reinstalling OS X.
If you’re not connected to the Internet, you’ll be asked to choose a Wi-Fi network from the AirPort menu in the top-right corner.
The Yosemite software license agreement screen appears. Read it and click Agree.
A sheet drops down, asking whether you agree to the terms of the license agreement. Yes, you did just click Agree; this time you’re being asked to confirm that you indeed clicked the Agree button.
If you don’t click Agree, you can’t go any farther.
Choose the disk on which you want to reinstall OS X by clicking its icon once in the pane where you select a disk.
If only one suitable disk is available, you won’t have to choose; it will be selected for you automatically.
Click the Install button.
A sheet asks for your Apple ID and password. Type them in the appropriate fields; click Sign In, and your Yosemite installation (or reinstallation) begins.
The operating system takes 30 to 60 minutes to install, so now might be a good time to take a coffee break. When the install is finished, your Mac restarts itself.
If you were reinstalling Yosemite on the hard disk that it was originally installed on, or upgrading from Mavericks, you’re done now. Your Mac will reboot, and in a few moments you can begin using your new, freshly installed (and ideally trouble-free) copy of OS X Yosemite.
If, on the other hand, you’re installing Yosemite on a hard disk for the first time, you still have one last step to complete. After your Mac reboots, the Setup Assistant window appears. You need to work your way through the Setup Assistant’s screens as described below.
Getting set up with the Setup Assistant
Assuming that your installation process goes well and your Mac restarts itself, the next thing you should see (and hear) is a short, colorful movie that ends by transforming into the first Setup Assistant screen (Apple Assistants such as this are like wizards in Windows, only smarter), fetchingly named Welcome.
To tiptoe through the Setup Assistant, follow these steps:
When the Welcome screen appears, choose your country from the list by clicking it once, and then click the Continue button.
If your country doesn’t appear in the list, select the Show All check box, which causes a bunch of additional countries to appear.
After you click Continue, the Select Your Keyboard screen appears.
Choose a keyboard layout from the list by clicking it once; then click Continue.
If you want to use a U.S. keyboard setup, click the U.S. listing. If you prefer a different country’s keyboard layout, select the Show All check box, and a bunch of additional countries’ keyboards (as well as a pair of Dvorak keyboard layouts) appear in the list. Choose the one you prefer by clicking it — and then click Continue.
The Select Your Wi-Fi Network screen appears.
Click the name of the wireless network you use to connect to the Internet, type in its password, and then click Continue.
If you don’t see the network you want to use, click Rescan. If you don’t use a wireless network, click Other Network Setup, and then choose one of the available options, or choose My Computer Does Not Connect to the Internet. Click Continue.
The Migration Assistant (also known as the Transfer Information to This Mac) screen appears.
Choose to transfer data, then click Continue, or choose not to transfer data, then click Continue.
If this is a brand-new Mac or you’re installing OS X Yosemite on a Mac and have another Mac or Time Machine backup disk nearby, you can transfer all of your important files and settings by following the onscreen instructions and connecting the new and old Macs via FireWire or Ethernet cable.
Transferring data can take hours — that’s the bad news.
The good news is that once the data transfer finishes, you’re finished, too. In other words, you can ignore the steps that follow (which are only for brand new installations with no data to transfer).
Goodbye and good luck.
Assuming you chose not to transfer data, the Sign In With Your Apple ID screen appears.
If you want to use your Apple ID with this Mac, type it (such as [email protected]) and your password in the appropriate fields, and then click Continue. Or, if you don’t have an Apple ID or prefer not to use one with this Mac, click Don’t Sign In, and then click Continue.
To learn more about getting an Apple ID, click the blue “Learn More” link. In a nutshell, it lets you make one-click purchases at the iTunes Store, iPhoto, or the Apple Store, and includes free iCloud membership.
The Allow iCloud to Use the Location of This Mac for Find My Mac sheet appears.
Click Allow or Not Now.
The Terms and Conditions screen appears.
Read the Terms and Conditions and click Agree. A dialog confirms your agreement. Click Agree again.
The Create A Computer Account screen appears.
Fill in the Full Name, Account Name (sometimes called Short Name), Password, Verify Password, and Hint fields, and then click Continue. Or, check the Use my iCloud Account to Log In checkbox. Then fill in the Account Name (sometimes called Short Name), and click Continue.
This first account that you create will automatically have administrator privileges for this Mac. You can’t easily delete or change the name you choose for this account, so think it through before you click Continue.
You can’t click the Continue button until you’ve filled in the first two fields. Because a password is optional, you can choose to leave both password fields blank if you like. If you do, your Mac warns you that without a password, your Mac won’t be secure. If that’s okay, click OK. If you change your mind and want to have a password, click Cancel.
Click on the little picture to the right of your name (it’s labeled “edit”) if you want to choose a different picture or take a picture of yourself with your Mac’s built-in camera.
If you choose to take a picture, click the Take Photo Snapshot button. When the picture appears, you can change its size by using the slider control directly below the image and/or move it around in the frame by clicking your face and dragging. If you’re not happy with this snapshot, click Retake a Video Snapshot. When you’re happy with it, click Continue.
If you choose to select a picture from the Picture library, click the picture you want to represent you — the butterfly, dog, parrot, flower, or whatever — and then click Continue.
The iCloud Keychain screen appears.
Click Set Up iCloud Keychain or Set Up Later.
If you choose Set Up iCloud Keychain, a screen requesting your passcode appears. Type your four digit passcode, and click Continue.
If you’ve forgotten your passcode or don’t have one, click Forgot Code to reset iCloud Keychain.
In either case, a verification code is sent to your iPhone or other Apple device; type it in, and click Continue.
The OS X Finder’s Desktop appears.
And that’s all there is to it. You’re done.
This article describes some of the commonly used features of Activity Monitor, a kind of task manager that allows you see how apps and other processes are affecting your CPU, memory, energy, disk, and network usage.
Open Activity Monitor from the Utilities folder of your Applications folder, or use Spotlight to find it.
Overview
The processes shown in Activity Monitor can be user apps, system apps used by macOS, or invisible background processes. Use the five category tabs at the top of the Activity Monitor window to see how processes are affecting your Mac in each category.
Add or remove columns in each of these panes by choosing View > Columns from the menu bar. The View menu also allows you to choose which processes are shown in each pane:
All Processes
All Processes Hierarchically: Processes that belong to other processes, so you can see the parent/child relationship between them.
My Processes: Processes owned by your macOS user account.
System Processes: Processes owned by macOS.
Other User Processes: Processes that aren’t owned by the root user or current user.
Active Processes: Running processes that aren’t sleeping.
Inactive Processes: Running processes that are sleeping.
Windowed Processes: Processes that can create a window. These are usually apps.
Selected Processes: Processes that you selected in the Activity Monitor window.
Applications in the last 8 hours: Apps that were running processes in the last 8 hours.
CPU
The CPU pane shows how processes are affecting CPU (processor) activity:
Click the top of the “% CPU” column to sort by the percentage of CPU capability used by each process. This information and the information in the Energy pane can help identify processes that are affecting Mac performance, battery runtime, temperature, and fan activity.
More information is available at the bottom of the CPU pane:
System: The percentage of CPU capability currently used by system processes, which are processes that belong to macOS.
User: The percentage of CPU capability currently used by apps that you opened, or by the processes those apps opened.
Idle: The percentage of CPU capability not being used.
CPU Load: The percentage of CPU capability currently used by all System and User processes. The graph moves from right to left and updates at the intervals set in View > Update Frequency. The color blue shows the percentage of total CPU capability currently used by user processes. The color red shows the percentage of total CPU capability currently used by system processes.
Threads: The total number of threads used by all processes combined.
Processes: The total number of processes currently running.
You can also see CPU or GPU usage in a separate window or in the Dock:
To open a window showing current processor activity, choose Window > CPU Usage. To show a graph of this information in your Dock, choose View > Dock Icon > Show CPU Usage.
To open a window showing recent processor activity, choose Window > CPU History. To show a graph of this information in your Dock, choose View > Dock Icon > Show CPU History.
To open a window showing recent graphics processor (GPU) activity, choose Window > GPU History. Energy usage related to such activity is incorporated into the energy-impact measurements in the Energy tab of Activity Monitor.
Memory
The Memory pane shows information about how memory is being used:
More information is available at the bottom of the Memory pane:
Memory Pressure: The Memory Pressure graph helps illustrate the availability of memory resources. The graph moves from right to left and updates at the intervals set in View > Update Frequency. The current state of memory resources is indicated by the color at the right side of the graph:
Green: Memory resources are available.
Yellow: Memory resources are still available but are being tasked by memory-management processes, such as compression.
Red: Memory resources are depleted, and macOS is using your startup drive for memory. To make more RAM available, you can quit one or more apps or install more RAM. This is the most important indicator that your Mac may need more RAM.
Physical Memory: The amount of RAM installed in your Mac.
Memory Used: The total amount of memory currently used by all apps and macOS processes.
App Memory: The total amount of memory currently used by apps and their processes.
Wired Memory: Memory that can’t be compressed or paged out to your startup drive, so it must stay in RAM. The wired memory used by a process can’t be borrowed by other processes. The amount of wired memory used by an app is determined by the app's programmer.
Compressed: The amount of memory in RAM that is compressed to make more RAM memory available to other processes. Look in the Compressed Mem column to see the amount of memory compressed for each process.
Swap Used: The space used on your startup drive by macOS memory management. It's normal to see some activity here. As long as memory pressure is not in the red state, macOS has memory resources available.
Cached Files: Memory that was recently used by apps and is now available for use by other apps. For example, if you've been using Mail and then quit Mail, the RAM that Mail was using becomes part of the memory used by cached files, which then becomes available to other apps. If you open Mail again before its cached-files memory is used (overwritten) by another app, Mail opens more quickly because that memory is quickly converted back to app memory without having to load its contents from your startup drive.
For more information about memory management, refer to the Apple Developer website.
Energy
The Energy pane shows overall energy use and the energy used by each app:
Energy Impact: A relative measure of the current energy consumption of the app. Lower numbers are better. A triangle to the left of an app's name means that the app consists of multiple processes. Click the triangle to see details about each process.
Avg Energy Impact: The average energy impact for the past 8 hours or since the Mac started up, whichever is shorter. Average energy impact is also shown for apps that were running during that time, but have since been quit. The names of those apps are dimmed.
App Nap: Apps that support App Nap consume very little energy when they are open but not being used. For example, an app might nap when it's hidden behind other windows, or when it's open in a space that you aren't currently viewing.
Preventing Sleep: Indicates whether the app is preventing your Mac from going to sleep.
More information is available at the bottom of the Energy pane:
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Energy Impact: A relative measure of the total energy used by all apps. The graph moves from right to left and updates at the intervals set in View > Update Frequency.
Graphics Card: The type of graphics card currently used. Higher–performance cards use more energy. Macs that support automatic graphics switching save power by using integrated graphics. They switch to a higher-performance graphics chip only when an app needs it. 'Integrated' means the Mac is currently using integrated graphics. 'High Perf.' means the Mac is currently using high-performance graphics. To identify apps that are using high-performance graphics, look for apps that show 'Yes' in the Requires High Perf GPU column.
Remaining Charge: The percentage of charge remaining on the battery of a portable Mac.
Time Until Full: The amount of time your portable Mac must be plugged into an AC power outlet to become fully charged.
Time on AC: The time elapsed since your portable Mac was plugged into an AC power outlet.
Time Remaining: The estimated amount of battery time remaining on your portable Mac.
Time on Battery: The time elapsed since your portable Mac was unplugged from AC power.
Battery (Last 12 hours): The battery charge level of your portable Mac over the last 12 hours. The color green shows times when the Mac was getting power from a power adapter.
As energy use increases, the length of time that a Mac can operate on battery power decreases. If the battery life of your portable Mac is shorter than usual, you can use the Avg Energy Impact column to find apps that have been using the most energy recently. Quit those apps if you don't need them, or contact the developer of the app if you notice that the app's energy use remains high even when the app doesn't appear to be doing anything.
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Disk
The Disk pane shows the amount of data that each process has read from your disk and written to your disk. It also shows 'reads in' and 'writes out' (IO), which is the number of times that your Mac accesses the disk to read and write data.
The information at the bottom of the Disk pane shows total disk activity across all processes. The graph moves from right to left and updates at the intervals set in View > Update Frequency. The graph also includes a pop-up menu to switch between showing IO or data as a unit of measurement. The color blue shows either the number of reads per second or the amount of data read per second. The color red shows either the number of writes out per second or the amount of data written per second.
To show a graph of disk activity in your Dock, choose View > Dock Icon > Show Disk Activity.
Network
The Network pane shows how much data your Mac is sending or receiving over your network. Use this information to identify which processes are sending or receiving the most data.
The information at the bottom of the Network pane shows total network activity across all apps. The graph moves from right to left and updates at the intervals set in View > Update Frequency. The graph also includes a pop-up menu to switch between showing packets or data as a unit of measurement. The color blue shows either the number of packets received per second or the amount of data received per second. The color red shows either the number of packets sent per second or the amount of data sent per second.
To show a graph of network usage in your Dock, choose View > Dock Icon > Show Network Usage.
Cache
In macOS High Sierra 10.13.4 or later, Activity Monitor shows the Cache pane when Content Caching is enabled in the Sharing pane of System Preferences. The Cache pane shows how much cached content that local networked devices have uploaded, downloaded, or dropped over time.
Use the Maximum Cache Pressure information to learn whether to adjust Content Caching settings to provide more disk space to the cache. Lower cache pressure is better. Learn more about cache activity.
The graph at the bottom shows total caching activity over time. Choose from the pop-up menu above the graph to change the interval: last hour, 24 hours, 7 days, or 30 days.
Learn more
Learn about kernel task and why Activity Monitor might show that it's using a large percentage of your CPU.
For more information about Activity Monitor, open Activity Monitor and choose Help > Activity Monitor. You can also see a short description of many items in the Activity Monitor window by hovering the mouse pointer over the item.