电脑已经与我们的生活息息相关，尤其在工作上，更是离不开电脑，我们需要用它来查找和存储资料，解决各式各样的问题，那么，当一台电脑需要换掉之前，我们该注意些什么呢？
If you have decided that you want to sell your old MacBook, so you can upgrade to a new one, you need to make sure that you prepare the laptop for sale.
You likely have a lot of files, passwords, and other information stored on the device, and you need to make sure that none of that information will be available to the person who buys your MacBook to decrease the risk of identity theft. Also, the more you clean up the device, the more attractive it is going to be when it comes time to sell it.
1. Back Up Your Files
The first thing you need to do is back up all of your files. You can go into OS X to learn how to back up all of your files before you erase them from the device. The last thing you want to do is lose anything important from your laptop. By backing up your files, you can be sure that you will have saved everything that you need, including precious memories such as photos and videos.
2. Sign Out of iTunes
The next step is to open iTunes and sign out. You will need to go to the menu bar and click on Account > Authorizations > Deauthorize This Computer. You will be prompted to enter your Apple ID and password. Once you have entered the information, click on Deauthorize. This will completely sign you out of iTunes, and no one will be able to log in under your account.
3. Sign Out of iCloud
Now you will need to sign out of iCloud. It is important to archive all of your iCloud data first, including features like Find My Mac. Then, click on Apple Menu > System Preferences. Next, click iCloud, and then click deselect on Find My Mac. Now you can sign out of iCloud. Go to System Preferences, click iCloud, and then Sign Out. You will be asked if you want to remove your data from Mac. As long as you are using the same Apple ID, your iCloud data will stay on other devices that have this ID.
4. Sign Out of iMessage
You should sign out of iMessage, if you use OS X Mountain Lion or later. Go to the Messages app, select Preferences > Accounts. Next, click on your iMessage account, and click on Sign Out. It is important to do this so no one else is able to access your messages, read them, and send messages out that are not from you personally.
5. Erase and Install OS X
The final step is to reformat the hard drive and reinstall OS X. There are instructions on Apple that will help you reformat the device easily. Once the hard drive has been reformatted the MacBook, you will need to reinstall OS X. The computer will restart and you will see a welcome screen, and be asked to choose your country or region. You can choose to do this now, or let the new owner do it later.
换电脑前的5件事，不要忘了哦。