Internal SSD Hard drive partition removal

Steve Mclinn wrote:

When setting up my 2018 MacBook Pro I put a partition on my internal SSD 2TB drive of 1TB for each partition. I had never used an SSD and was old school in my thinking about setting up drives for speed etc. Anyway, I am now out room as I use a lot of data storage for music and video work so I need to use partition 2 in whole or part to give more space to the 1st partition. I would be open to eliminating the partition entirely, but I do not want to lose any data on the OS partition.

If I backup the data on Partition 2 can I remove the partition? If I remove the partition will all data appear on the new single drive? Thank you for any advice or direction where to find this info.

Well you can try that. DiskUtility is known to have issues reclaiming "partition" space in the new apfs format. You are at risk.

The alternative—

You will have to erase/reformat/initialize the drive as new— this will erase all Data.

DiskUtility>View>Show All Devices

Erase and reformat a storage device in Disk Utility on Mac

https://support.apple.com/guide/disk-utility/erase-and-reformat-a-storage-device-dskutl14079/21.0/mac/12.0

How to reinstall macOS

Recovery (both M1 and Intel) — https://support.apple.com/en-us/HT204904

You need a viable (preferably more than one) backup of your user data to restore.

restore items backed up with Time Machine

https://support.apple.com/guide/mac-help/restore-files-mh11422/mac

3-2-1 Backup Strategy: three copies of your data, two different methods, and one offsite.

I did the same thing years ago. Between my own personal lessons learned over the years and trying to assist other people here, I now try to dissuade people from using multiple partitions especially since external drives today are so fast. There may be a few limited cases where multiple partitions may be necessary, but I think that should be extremely rare.

You can get older macOS installers from links within this Apple article which also includes instructions for creating a bootable macOS USB installer:

How to create a bootable installer for macOS - Apple Support

FYI, If you have more than one Mac (or more than one macOS boot drive on this Mac), then why not download & archive the older macOS installers you are interested in. Just create a folder and copy the macOS installer app from the Applications folder into the new folder (e.g. "Install macOS Mojave.app"), then use Disk Utility to create a compressed read-only .dmg archive file. Once you have the installer app, just about any Mac and macOS can create the bootable USB installer (at least more options than there are to download the macOS installers). Don't store a macOS installer in its app form as it may change over time without you knowing it even if you move the installer to another location.

I actually used an old hard drive pulled from an old computer and created multiple macOS bootable installer partitions on the single used hard drive so I have easy access to reinstall any OS of my choice when needed. I also keep a .dmg archive image of each installer app as well in case this old drive dies on me since I am running out of older working computers to be able to download and/or extract the macOS installers. It would really be nice if Apple provided access to all of these macOS installers outside of the App Store in a form that any OS could be used to create a bootable USB installer since not everyone has access to another compatible Mac. While Internet Recovery Mode is nice, it does not always work as intended plus it does not provide access to each OS compatible with a particular Mac.

Make sure to have a good backup of your macOS volume as well because modifying partitions is a risky endeavor every time.

This is exactly why I never recommend anyone partitioning their drives, especially their main boot drive.

You should always have frequent and regular backups of your computer and all extra partitions/volumes and all external media which contains important & unique data. It is impossible to recover accidentally deleted data from an SSD after the Trash has been emptied. Plus an SSD can fail at any time without any warning signs (even a brand new SSD). In addition a 2018+ Mac uses a T2 security chip which hardware encrypts the data on the SSD which is soldered to the Logic Board. There is no way to recover any data from a non-functioning Logic Board without having someone repair the Logic Board itself (Apple won't do it). If anything ever happens to the T2 chip, then there is absolutely no way to recover any data, plus the T2 has been known to become corrupted with some macOS updates which updates the system firmware which means you lose your data.