how do i get rid of system data?

You seem to be missing the point here! Why should I have to go through all the hassle and lost time doing a factory reset just because Apple is incapable of fixing what is clearly a software problem! We pay enough for these devices to be able to expect seamless operations, we do not expect to be spending time and money trawling the internet for solutions to a problem that Apple should be addressing!

Right now my systems data is 72.67 GB. I’ve restarted the phone and deleted pretty much everything. Is this normal for I-phones?

Don’t you think I haven’t already done all this? The phone itself has been offloading apps to make more space that it can then fill up with system data. What a ridiculous piece of software, I can’t believe that a fix hasn’t been issued!

And can you tell me, is the same true on my Mac? That it will flush when needed and if I simply don't like it, I need to restore and manually rebuild?

I was hoping that setting up a fresh 14-inch MBP from a Time Machine backup would clean up the System Data cache but all 260 GB of it returned (more data than all other types combined!). Cocktail doesn't seem to clear it out much, if at all.

I'm assuming you're look at System Data, inside iPhone Storage. First, System Data is not stored in iCloud, but locally on your iPhone.

System Data contains cache files from your apps, and from the system itself. The reason it is stored is to speed up the loading process when you open apps, or something else. If those files were not saved, things would take longer, and use more battery, because everything had to be loaded, over and over again.

That said, it is not possible to manually delete System Data. iOS works in such a way that when there is a lack of space, the system cleans itself. So if you are in the process of downloading a large file and there is not enough space, then iOS will start deleting old cahce files that have not been used for a long time, thus freeing up space.

So there is actually no need to worry about the System Data. It all happens automatically. The only thing you can do yourself is to reboot your phone once in a while, it also starts a small cleanup.

I hope I got your question clarified.

So why has system data been existentially growing on my phone until it now takes up 20+gnome and has now blocked the phone. Can you explain to me what use these back up files when they have rendered my phone useless! Shall I return it and ask for my money back?

Try restarting your iPhone. The system clears the cache data when the phone restarts. It is generally a good idea to restart the phone once in a while, just like you did in the old days with your PC when it did not work as it should.

If your problem is still going on, then I would recommend doing an iCloud Backup and a Factory Reset to get it completely cleaned out. However, the best thing would be to do a Factory Reset WITHOUT loading an iCloud Backup afterwards, as that way you get rid of everything. But it takes time to set up all the apps again, so it's up to you how much time you want to spend.

1) To make an iCloud Backup:

How to back up your iPhone, iPad, and iPod touch - Apple Support

2) To do a Factory Reset:

How to factory reset your iPhone, iPad, or iPod touch - Apple Support

3) To restore from an iCloud Backup or Computer:

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Your phone will not be blocked even if there is no more space. But it is clear that if your phone's memory is full, then it needs to be cleaned up.

On your iPhone, go to:

Settings -> General -> iPhone Storage

There you can see everything that takes up space on your iPhone. You can also delete the apps you no longer use to free up memory.

Problems need to be solved, and sometimes you have a responsibility to do it yourself. I've also paid a lot of money for my car, but I can not expect that I will never see a fault lamp, or that something breaks. Sometimes it's my own fault that my car broke down, also I have to spend time in a workshop, and maybe even spare my car for a few days, with all the hassle that comes with it.

The data you see comes from somewhere and it is not loaded on the phone from the start. Therefore, take responsibility and fix your phone with the advice you have been given. It's possible that this is a software problem, but I can not solve it. I can just give you advice and as a thank you for that you scold me.

Cars require maintenance and cell phones require maintenance. Everything requires maintenance if it is to work properly.

I eventually went through the whole rigmarole of backing up my phone and then doing a full factory reset during which iOS 15.5 was installed and now, lo and behold, my System Data remains stable at just under 5gb. Perhaps I'm being paranoid but it makes me wonder of there was a solution to the problem built in to the update but Apple weren't going to own up to it! Fingers crossed it won't happen again!

See my post above, the only way to fix it seems to be back up the phone and do a full factory reset! It’s a pain to do but seems to fix the problem.

I very much appreciate your thoughtful response, --JS--, thank you!

Thank you for asking this question