How was I able to install macOS Ventura with low disk space?

"Time Machine Backup, if Not Run Frequently, will generate Snap Shots which will be stored on the Internal Drive of this computer.

They will remain there until the External Drive is actually attached to the computer and TM Backup is run.

Thereby, the Snap Shots are effectively Purged from the Internal Drive after they have been moved to the TM Backup Designated Drive."

That explains the free space regained. My last TM backup was over a month ago.

I do try and keep my OS partition about 25% free. With one of the recent updates to macOS, they moved the cloud accounts (OneDrive, Google Drive, etc.) to the OS partition. I had configured them on a different partition separate from the OS, but after that update all cloud files were automatically moved to the OS partition. This reduced the free space I used to have before the change.

But anyways, I still think that Ventura is not as major an update that Catalina was. And it probably requires lesser free space compared to both Catalina and Monterey. Currently I have close to 30 GB free space on the OS partition, which should be plenty sufficient for any updates to Ventura.

Thanks for this very useful info.

No, I didn't. I wanted to do it after downloading Ventura, so I could include the OS also in the backup. But the system automatically rebooted after the download was completed. This is something that should not happen. Users should be allowed to decide when they want to run the update.

My guess is that the system already identified disposable files and space to be regained (in this case about 12 GB), and this is probably why no low disk warning was issued, and the update completed successfully.

"Install macOS updates" is probably the setting that forced the update without any option to postpone it. I have disabled it now. Going forward, hopefully I'll be able to decide when to update once the update file is downloaded.

That's true.

I wanted to do the backup before the update proceeded (after downloading the update file) and I was expecting to see the error since my laptop was low on free disk space. I also did not expect the update to proceed forcefully without giving me the option to postpone it. I'll keep these in mind next time.

Be it Windows or Mac, my OS is always on a separate partition that is used exclusively by the OS. All my files and personal data are always on a separate partition. This has both security and other very specific, useful benefits with no disadvantages.

It doesn't matter how many partitions you have on your internal disc. It makes no difference from efficiency point of view as long as there is sufficient free space in each partition.

One other reason I have multiple partitions is because I also have Windows installed on my Mac using Bootcamp. They both run really well and I have a partition in exFAT (on the internal disk) where I save a lot of my files so I can access them from either OS.

My setup has been like this for 3 years now since I bought my laptop. Everything runs absolutely fine. I have even formatted, resized, repartitioned my disk several times during this period. This includes installing a fresh copy of the OS and restoring/ migrating data afterwards when there was a low disk space problem. There has never been any issue. These activities don't damage the hardware in any way.

Of course, I do backup everything to my external SSD first before playing around.

I thought so too. Good that this year the update process was super smooth. In the previous two years, I had to install a fresh copy from recovery and then migrate all the data. This meant the Launchpad had to be redone, accounts had to be signed back in, cloud files had to resync, etc. .... basically a lot of useless work avoided this time.

What is also observed is that after the update, I see the free space on my OS partition has increased to about 30 GB. An addition of 12 GB! I hope I haven't lost any of my files.