How can I find the date that I upgraded to High Sierra?

Solution 1:

Follow these steps:

  1. Go to Apple > About This Mac
  2. Click on the System Report button
  3. In the lefthand Sidebar scroll down to Software and select the Installations option
  4. In the righthand pane you will see a list of software. Scroll through the list until you see the macOS High Sierra installations (see screenshot below as example):

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