I have a MacBook Pro early 2011. I'm thinking if to upgrade to Sierra. Right now I have Mavericks.
If I backup my current system using the time machine, when I will restore from the backup, it will be back again Mavericks?
Time machine can't hold backups of the operating system. It only backsup your personal files. The steps below will allow you to downgrade.
macOS will not allow you to run an older installer so you will need to circumvent it by doing it from a bootable drive.
You may also consider running multiple versions of OS X. You can do this by partitioning Macintosh HD. It doesn't require a format so your files are safe. Do the same steps below except first partition the hard drive before restart. In the installer, select the other partition.
How to do it:
launch terminal and run this command:
sudo /Applications/Install\ OS\ X\ El Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El Capitan.app --nointeraction
hit enter and type your password;
This shows how to downgrade to El Capitan. The process is the same for Mavericks. http://www.macworld.co.uk/how-to/mac-software/how-downgrade-from-macos-sierra-el-capitan-remove-macos-sierra-3581872/
Let me know what happens. I hope this is helpful.
PS: backup any files you want to save from the flash drive because it will be erased.
As long as you have a Time Machine backup from before the upgrade was done, on a system running Lion or higher, and the drive is an external USB or FireWire drive with a GUID Partition Table, yes, it is possible to use Time Machine to restore the OS as well.
1) Boot to Recovery Partition on your external Time Machine drive (it should have a copy of the computer's recovery partition).You can also use the internal Recovery HD, which will be fatser
2) Select the "Restore from Time Machine backup" option in the Recovery menu. Make sure you select a backup made before you upgraded to the version you are attempting to downgrade from.
4) When it's done, reboot, and enjoy your new old system - a perfect copy of the old one, including the OS.
Please see here for more information: https://support.apple.com/kb/PH25593?viewlocale=en_US&locale=en_US http://pondini.org/OSX/RecoveryHD.html