Downgrading to 10.13 question

[sfphoto]

Purchased a 2015 MacBook w/ Monterey. Need to use High Sierra.

Is it fine to boot the Mac from an external 10.13 volume (cloned from another Mac), reformat the MacBook internal, then clone the external to the internal.

OR

Is formatting enough or does 10.13 need to actually be installed?

Thanks in advance.

 

[Joeronzk]

1. Make a 10.13 bootable USB first.
2. Backup the data.
3. Ease the internal drive.
4. Boot the Mac from USB and start installing 10.13

 

[MacBiter]

Is it fine to boot the Mac from an external 10.13 volume (cloned from another Mac), reformat the MacBook internal, then clone the external to the internal.

That's how I did something similar (in that case booting from a Mavericks clone, using it to erase the Mac's main drive, then cloning from the clone to the Mac using CCC).

 

[sfphoto]

Thanks everyone - cloning seemed to be enough, new drive is working fine.

Slow start up though, 30sec w/ High Sierra & no log-in items (listed)

 

[MacBiter]

Thanks everyone - cloning seemed to be enough, new drive is working fine.

Slow start up though, 30sec w/ High Sierra & no log-in items (listed)

Is it a HDD or SSD? 30 seconds sounds about right for a HDD, perhaps better than normal.

 

[sfphoto]

Is it a HDD or SSD? 30 seconds sounds about right for a HDD, perhaps better than normal.

PCIe - non Apple though