Installing a new macOS without too much fuss or lost data

Hi all,

I mentioned in my recent newsletter I am having troubles on the Mac’s I upgraded to 10.13.2.  On my MacBook Air I sometimes have a locked screen, and / or I cannot enter a password (on the lock screen) and in either case have to reboot cold.  On my MacBook Pro I lose connection to the network.  I am connected via a dock to a physical cable, as well as I have my Wifi on.  BTW, Apple has told me that in that scenario the Internet, or file copy type actions will go over the physical network, and collaboration type stuff will go over the Wifi - so things like AirDrop for example. If I disconnected my physical network, and paused, then connected it back, no more problem.

When I escalated this to Apple, thinking with two impacted machines, that I would be asked for logs or something.  But I was told to re-install macOS.  That is not scary, but I was trying to help and to be told to re-install was OK for me but no help for learning or for other people.  They did escalate me to an Enterprise guy, not sure what tier.  He suggested some config changes to generate logs - or more logs - but I figured to get things back to normal. So this article will re-install macOS to solve this issue - I hope.

BTW, I have done this using an ISO burned to CD, and an ISO burned to USB and the USB is much faster so that is what we are going to do here. So make sure you have an USB thumb drive with at least 8 GB of storage. I am using a DataTraveler C10 8 GB memory stick.

Protect Yourself

You need to have both an image and a Time Machine backup. Once that is done, you should continue.  BTW, the TM backup is what we will use to customize the install so it looks the way it needs too.  The image backup (I use SuperDuper) is in case things go really bad.

Get the bits

So now we need to download the macOS High Sierra 10.13.2 ISO.  It is not quite as easy as it sounds but it is not hard either. Enter the App store and look for macOS.

Download, BUT, no install

So we now do the download, but we do not let the install process start. So we push the Download button to start things off.

It will calculate and then it will take a bit of time. Once you see the install screen you know it is time to quit.  Right + click on the icon in the task bar and select Quit.

Now we have the bits downloaded we need to erase our memory stick and then write out to it as a bootable format.  I have trouble with both of those steps when my anti-virus software is running so I disable it.  Which hurts as I do not normally do that.

I normally will do command key and spacebar to get spotlight search up and type Disk Utility and return (or look for it in the Applications folder).  After it starts, select your USB and erase it.

Next we need to write out to the USB memory stick the bits and make it bootable.  So we start  Terminal. We need to enter the following into the command line.  BTW, my memory stick is named highsierra so that is what I used in the command and you would substitute your own USB memory stick name. You will be asked for your password once in this terminal session. BTW, if you copy and paste the command below the double dash in front of volume will change to a single dash and an error will occur.

sudo /Applications/Install\ macOS\ High\ -volume /Volumes/highsierra

Once you hit Y, you will see some progress.

This will take some time. The longest phase is the copy installer files to disk.  But you know it is working by watching the very fast blinking light on your USB stick.  If you have a light that is.

But soon it will be done.

So we now have a USB memory stick that is in fact a High Sierra installer.  Next we need to use it.

Installing macOS High Sierra

We need to boot to that memory stick.  So power off, and boot, and while booting hold the Option button down. You should be prompted for a boot device.  See my screen below.

Select the Install macOS High Sierra option.  Then select your Wifi network. You can see my Time Machine back up drive, the existing boot device, and the new install option as well.

Above I have selected the install option, and my Wifi network. Once I push the circled arrow seen above it takes a few minutes and then you see a Utilities screen.

Since I am concerned of how my update has gone, I am going to do a destructive update.  So we need to use the Disk Utility to erase our drive.

After you select Disk Utility, you will see it start and all of the attached disks will be displayed.

Select your disk - make sure it is the right one - and select the Erase button on the Tool Bar. Once erased the screen will change to be something like below.

My disk was encrypted, as you can see above, but the password is not required when I erase it.  However, if I was not going to erase it, and just install to it, I would need my password for the Encryption.

After you exit from the Disk Utility you will be back on the Utilities screen.

One of the times I went through this, when I tried to install it did not, and it was a circle where I ended up back at the menu above.  I was able to do a cold restart, and try again and the install actually worked.

Once you select Install macOS, you will see the following.

Next we select the right hard drive.

After you select the drive and Install, it takes a while.

It will restart once.  After that it takes a while.

Sorry about picture quality.  There is 10 minutes remaining.  And that is not to finish time, but in this segment there is 10 minutes left.

So this is the install that most of us are familiar with.  We select the proper country.

Now the language choice.

Wifi choice now.

Now the good stuff.  We make the choice to use Time Machine to transfer my info to this newly install Mac.

We are confirming here the source to use.  The MBA hard drive is Rock HD, and the backup is RockHDBU.  Plus it has a Time Machine icon so we know we have chosen the right one.

It takes a few minutes for all the totals to fill in, but you can hit Continue sooner if you like.

I set my password - in fact use the same one as this account had before.

Now we have a small issue.  It is in fact correct, that the newly installed macOS on the MBA does have an older version of iTunes. So I hit Update.

It does not take long, and when I continue, it wants to upgrade iTunes again.  Odd.  I push a few buttons - Skip, Cancel, and finally upgrade, but it restarts the computer.  But, that is Ok, as it comes back to the start again of the install.

So we select Country, Language, Wifi and source of information to transfer to this new install. After that we set our password. This time there is no comment about iTunes. The next screen we see is the FileVault Disk Encryption one.

I do not want my iCloud account to unlock my FileVault (I really like the Apple full disk encryption) as I think that makes things a little to easy for potential exploit. So lets unselect the Allow my iCloud option.

On the next screen you see the complex password that can disable the encryption with (screen not shown here!). After that you see the transfer of information.

After a bit, you will see a time remaining.

My experience is that the time is not accurate.  But it does still take some time. It is slow, but also dependent on the medium as well.  In my MBA I have only a USB connection with my external drive. So it took around 3 hours for this transfer.  I suspect my MBP with USB 3.0 will go much quicker!

Once it finishes, you will have to reconnect to iCloud, and you should reconnect on the iTunes store but you should be done.

For testing purposes, I checked both my Apple and Microsoft email clients to make sure they worked, then Evernote and 1Password, and they all were good. BackBlaze and Time Machine did there thing properly too.  I also confirmed that FileVault was enabled.  No reason to suspect it wasn’t but just being careful.  So this turned out to be a pretty smooth process.

This is not a destructive install in that while we did destroy the existing partition, we did restore all of our files and data but this is what Apple said would solve our issue.  And it was good to do on my MBA since it had done a lot of beta in the last year or two and cleaning it up was a good idea.  If it also solves the issues - which so far it has - that is a very good bonus.

I will update this article as I learn or confirm more.


  • 1/1/18 - I can confirm now that this rebuild has solved my network issue on my MBP.  So things have been working very smooth and in fact how I expect them too.  I can also confirm that after this longer testing that no other issues has developed due to the reinstall.
  • 12/21/17 - did the update on my MBP and it was seriously faster.  The USB Type C does help a lot.  I realize another reason to do this is that you get rid of all of the OS related cruft that has built up over the many versions.  Unfortunately, since I use Time Machine to restore my data I still have any data related cruft but it is a good thing to have at least the OS cleaned up.
  • 12/21/17 - I can confirm that this destructive install fixed my issues on the MBA.  Not any issues seen in the last couple of days so that is very good.  No other issues developed out of this install either.
  • 12/18/17 - updated with the watch out for the — changing to a - when you copy and paste.
  • 12/18/17 - published.


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