Two ways to reinstall your Mac system:
1, online remote reloading.
2, the production of a USB flash drive to reload.
Theoretically the first is relatively simple, but it will be more time-consuming, in practice, because the online version of the system download is lower than my current version of MacOS, resulting in the inability to install, so you can only use the second method.
Install a software to ensure the U-disk installation is successful
http://diskmakerx.com/#
Note that after the production of a USB flash drive, the first format of the original SSH hard disk, and then into the U disk installation can be.
Reinstall the system, work a day, basically put the necessary software are installed back.
After the installation of the new system plan:
1. Plan the download files and put them into different folders.
2. Use 1Password to manage passwords for each website
3. Scheduled backups
U disk re-installed Macos-sierra system