Don’t worry; it won’t affect your files, data, apps, user settings, etc. Only a fresh copy of macOS High Sierra will be installed on your Mac again. … A clean install will delete everything associated with your profile, all your files, and documents, while the reinstall will not.
Will upgrading my macOS delete my files?
No. Generally speaking, upgrading to a subsequent major release of macOS doesn’t erase/touch user data. Pre-installed apps and configurations too survive the upgrade. Upgrading macOS is a common practise and carried out by lot of users every year when a new major version is released.
Does installing a new macOS delete everything?
Technically speaking, simply reinstalling macOS won’t erase your disk either delete files. You probably don’t need to erase, unless you’re selling or giving away your Mac or having an issue that requires you to wipe.
Do I need to backup Mac before upgrade?
New versions of Apple’s operating systems are coming to your iOS devices and Mac. If you’re planning to upgrade your Mac or iOS devices with Apple’s newest software, you should make it a point to back up before you install these new versions. …
How do I update my Mac without losing data?
How to Update & Reinstall macOS Without Losing Data
- Start up your Mac from macOS Recovery. …
- Select “Reinstall macOS” from the Utilities Window and click “Continue”.
- Follow the onscreen instructions to select the hard drive you want to install the OS on and start the installation.
Does Mac delete old OS?
No, they aren’t. If it’s a regular update, I wouldn’t worry about it. It’s been a while since I remember there was an OS X “archive and install” option, and in any case you would need to select it. Once it’s done it should free up the space of any old components.
What happens if you reinstall macOS?
2 Answers. It does exactly what it says it does–reinstalls macOS itself. It only touches operating system files that are there in a default configuration, so any preference files, documents and applications that are either changed or not there in the default installer are simply left alone.
Is it safe to upgrade macOS without backup?
You can normally perform every update to apps and the OS without any loss of files. You can even install a new version of the OS in place, while keeping your apps, data and settings. However, it’s never ok to have no backup.
What happens if I don’t backup my Mac before updating?
Mac Backups before Upgrading
It ensures that you can not only restore your entire drive if necessary, but also easily recover a previous version of a corrupted file. … This is because a fire or flood would likely destroy your backup drive along with your Mac. So please, back up your Mac before something goes wrong.
How long should a Mac backup take?
If it’s just a normal backup it’s unlikely to take more than five minutes. If you feel that the Time Machine backup is taking too long there are ways to speed it up, which we look at below.