Yup . Facts don ' t do well there . Early on I wanted to trump a fair shot because hey , he was different . But looking stuff up I realized he was nuts . So I asked for a source on a claim . Bam , banned . The was early on in the primaries . <| sep |> Trump got swagger <| sep |> The slowed down 800 % version is pretty relaxingQspuCt 1 FM 9 M . <| sep |> Not true . Reinstalling macOS does not erase your startup disk . However , OP , you will want to make a USB installer , as it ' s likely you ' ll encounter the same failed install if performed with the recovery partition . Get a friend with a Mac to download macOS Sierra from the App Store and Install Disk Creator from macdaddy . io . Connect a thumb drive with at least 8 gb of storage to his computer , reformat the thumb drive as extended journaled , guid partition table these are the defaults . Launch install disk Creator after macOS Sierra is done downloading . It should automatically appear in install disk Creator , otherwise just browse for the Sierra installer in Applications . Select the attached thumb drive as the location to create the install disk then start . Once done , connect the thumb drive to your Mac , boot while holding the option key to get to the startup manager , choose the drive named install macOS Sierra or something like that from the list , and install the OS on your startup disk .