Generally installing OS X takes about 20 to 40 minutes, but there are times when the install process may take longer or seem to hang at a specific step. This may be especially true if you’re using Apple’s new Internet-based installation for Lion.

How long does it take for macOS High Sierra to install?

The macOS High Sierra installation time should take about 30 to 45 minutes to complete if everything works right.

Will Big Sur slow down my Mac?

Why is Big Sur slowing down my Mac? … Chances are if your computer has slowed down after downloading Big Sur, then you are probably running low on memory (RAM) and available storage. Big Sur requires big storage space from your computer because of the many changes that come with it. Many apps will become universal.