Why are you thinking of a clean install ?

macOS isn’t Windows, it doesn’t tend to suffer from that same “bit rot” that an aging Windows install can.

My MacBook Pro M1 Max is a effectively running the same install of macOS that has been migrated through all the versions of macOS since whatever my 2012 MacBook Pro came with (and was migrated via another MacBook Pro over that time).

That old install is behaving just as well as my Mac Mini with a much more recent fresh install.

Unless you are having specific issues, doing a clean install of macOS as opposed to upgrading really isn’t necessary.

This is one of the benefits of macOS not having a central registry, Apple retiring old feature rather than supporting them forever and not having the equivalent to DLL-hell that Windows has suffered from (though DLL-hell is less of a issue nowadays). And also Apple’s decision a few years ago to make all the system files totally unwritable (think Windows has some of that now but not in the way macOS does).

Worth reading Mark Russinovich blogs from a few years ago where he described why the idea that the registry causes slow downs is actually technically incorrect. The registry is a database, like any other database it is not read as a text file, it is random access.

the old "bit rot" was mostly caused by DLL-Hell, which has been effectively solved by the OS virtualising the directories that applications write DLLs to without using system calls. This stops one badly behaved application from breaking the OS.

Apple went the other way and decided to break older applications, which is why subscription versions of MS Office and Adobe products became very very popular on macOS.

Now and again the Mac seems to go on a go slow, certainly with higher CPU stuff, that it did nto do before. Also seems not to load pages from the web as fast for some reason, but the speed internet wise is fine.

Also, if I do decide to go back to Sequia, then I will have to do a clean install.

In reply to a post by zyborg47:

It seems umm, not sure really. It seems very A.I integrated, one of the reason I got away from Windows was because it was too A.I based.

Some things look good, but not sure if I will bother to update.

Running it so far on a Mac Studio and a MacBook Pro M4 Max and so far it hasn't broken anything.

I was slightly worried about the driver extension compatibility on an ATTO ThunderLink adapter on the Studio but that seems OK.

I can't see anything too AI shouty either, Siri AI (beta) is disabled by default as is the ChatGPT integration likewise in a benign state. So I wouldn't worry about either of these.

I've installed it on an external SSD on my M4 Mini Pro and initial feeling is that it does subjectively feel much snappier than the Sequoia that I'm running (even though the internal SSD is considerably faster than the external one). But, at the moment I'm still sticking with the "if it ain't broke" philosophy and continuing to run Sequoia. The M4 pro, with 64G of RAM, is plenty fast enough.

I may do that if I can find a spare drive and have a peak.
i have just reinstalled Sequoia, don't want to do that too often. I printed out a list of the software I had on the machine and there is a lot I had on I don't use. Even so it have taken me a while to get tot he stage I am at and while I 99.9% of the software i want on the machine, I still need to se some up.

Still having the issue of a bit of a delay before some sites start to display, including this one for some reason. I don;t remember having it before, maybe I did. i will put the PC on in a bit and see if that does it.

64GB is a fair bit of ram, certainly for a Mac as it would not be cheap. I have 16Gb on a M2 pro and to be honest for the most part it works okay. I may update one day, see how things go moneywise and what doc says when i have tests in a few weeks time. I do have money saved, but with no work at the moment it would not take long to go down.
Anyway at the moment this Mac does me fine, I did think about getting a Neo just for a laptop, but i am not a fan of laptop, so maybe a Ipad. I will see what happens.

Anyway, the machine is back up and working with Sequoia and seems to be okay.

I run a number of virtual machines, so find the RAM useful. It would be much more expensive nowadays but I got it as an Apple refurbished a while ago. I buy all my Macs that way - normally saves a few hundred quid and they’ve all been as good as new. You just need to wait a while for the right one to come up.

In reply to a post by TinyMongomery:

I run a number of virtual machines, so find the RAM useful. It would be much more expensive nowadays but I got it as an Apple refurbished a while ago. I buy all my Macs that way - normally saves a few hundred quid and they’ve all been as good as new. You just need to wait a while for the right one to come up.

Unfortunately there's not much good news on the horizon when it comes to RAM prices either...

https://www.macrumors.com/2026/09/17/apple-higher-ra...

In reply to a post by Pheasant:

Unfortunately there's not much good news on the horizon when it comes to RAM prices either...

My company used to provide Macbook Pro 14" to most staff, some with 32 or 64gb most with 16gb. Now the majority are getting Macbook Air. The Windows side is equally suffering, RAM allocations are down, people told to try their experiments in "cloud" which needs funding.

The technology industry is slowly, but surely, killing itself.

Lenovo now want an extraordinary £1080 for an extra 32GB of RAM (£33.75 per GB) on ThinkPads and Apple want £25 per GB on Macs for extra RAM.

It's all more than slightly unhinged by the AI juggernaut

Edited by Pheasant (Fri 18-Sep-26 18:02:25)