Sometimes, in some situations, MacBook Pro or MacBook users may need to reinstall MacOS Sierra. This could be either be done as a troubleshooting technique only or for any other reasons that require them to reinstall Mac Sierra. There are some steps you need to perform resinatlling macOS such as backup of data and singing out of iCloud, iTunes, iMessage.

To download and reinstall MacOS using recovery, you need an internet connection that meets a set of necessities are mentioned below:

The connection should be configured to use DHCP (Dynamic Host Configuration Protocol) over Wi-Fi or Ethernet. Internet connection doesn’t use 802.1X or other certificate-based authentication or proxy server.

If the internet connection uses WPA-Enterprise security protocols or WEP, then you can use MacOS recovery. If it is on a captive network, then use MacOS recovery not MacOS internet recovery. If proper connection is established, then perform following mentioned steps to reinstall Mac OS.

How to Reinstall macOS Sierra?

• In the menu bar, choose Apple menu, >Restart. As your Mac restarts, hold down Command +R key until the macOS Utilities window appears.
• Select Disk Utility, then click on Continue.
• Click Format pop-up menu, choose Mac OS Extended and click on Erase.

Note: Erasing the disk removes all the info from the disk. Always keep back up of data in any storage device.

• After the disk is erased, choose Disk utility then Quit Disk utility.
• Select Reinstall macOS, click on Continue button, then follow the on screen instructions.

There are some other ways also to re-install macOS Sierra, one of which is through Time Machine backup. In case, if you have kept backup then you can restore macOS from that backup. But note that doing so will delete all the disk data you are restoring then replace it macOS Sierra and other data from the backup you have created.

To reinstall macOS Sierra, enter into recovery, then select Restore from Time Machine Backup and follow the onscreen instructions to complete the process.

If you have not created any backup for your Mac data and you lost it after reinstalling macOS Sierra, then you will need a professional Mac data recovery software to restore them. Recover Mac software supports all macOS system including the newest Sierra, Yosemite, Mavericks, Lion, Mountain Lion, Leopard, Snow Leopard, etc. For more details, you can visit this link: http://www.recovermac.net

Features of Recover Mac software:

• This software is capable of recovering lost data after reinstalling macOS Sierra within few mouse clicks.
• It is also applicable to restore data from external hard drive, iPod, memory sticks, USB drive, etc. on Mac based system.
• Preview option is available in Demo version of the software, using which you can view the recovered data before saving them to other storage device.
• The software has  quick tool to find files on Mac volumes and can recover Mac hard drive data on the basis of size, name, date and file type.
• Recover Mac software is capable to recover data from Mac hard drive which can support file systems such as FAT 32, FAT 16, NTFS, NTFS 5, ExFAT, etc.
• It also performs Mac data recovery from different types of hard drive interfaces such as SATA, ATA, PATA, IDE, etc.