
Other issues – There could be numerous other issues with your Mac as well that would demand a reinstallation.Malware attack – A virus or malware can also infect the core function of macOS and would demand a complete reinstallation of the tool.In order to fix it or run troubleshooting, you would need to reinstall the OS. Corrupt OS – Ideally, your macOS can get corrupt or compromised due to different reasons.Mostly, the issue is resolved by visiting the Mac recovery mode. Startup issues – Apart from the firmware, there would be a problem with your Mac's startup or bootstrap program as well.It can happen when macOS seems to malfunction and can't complete the needed operations. Firmware issues – Mostly, a firmware issue related to macOS demands a reinstallation of the operating system.The following are some of the common problems that force a complete reset on a Mac. There are all kinds of reasons for us to reinstall macOS on the system. Recover Erased Files after Reinstalling Mac OS.Troubleshooting: How to Reinstall Mac OS?.Then choose to reinstall the OS and the disk will not be greyed out this time.Once it loads, go into Disk Utilities and Erase the main drive and select the journaling formate style.Step 2 (now that you are booted on a the USB stick and not the main HD): When it’s done, insert your USB drive into any Mac, then launch the installer by holding down the Option key.Select your flash drive from the drop-down menu.This is should be located in your Applications folder. Open Disc Creator and click the “Select the OS X Installer” button.If you have any other data on that flash drive, back it up now, because the installer will delete everything on it. Insert an 8GB (or larger) flash drive.Download the macOS Sierra installer and Disk Creator.The easiest way to create a USB flash installer is with the free program, Disk Creator.

You need to create a USB flash installer, then reformate the drive then reinstall. What the issue is, you are trying to modify the drive you are currently working on which it doesn't like. I'm writing this as I search for it and found solutions and none of them worked and I noticed I wasn't the only one.Įasy solution is hold down command + R and get into disk utility, select the main HD and select File > "Enable journaling" but if you are like me, it was greyed out.
