Is there any point to a clean install?

Cartoonguy wrote:

Using a Mac Studio and have been having problems with external drives ejecting randomly and other issues including periodic system crashes, which was really rare before I moved from my older iMac to my Studio, so I'm thinking something is wrong. Like today I just noticed that my Time Machine back up was not even online for a week!! The ejecting is not limited to one drive and I fear it is also corrupting the drive as I get the message that it was not ejected properly.

Inclined to clean things up using by doing a clean install, but read online that with Ventura and M1 Macs, there is no need, because...

Should I do a clean install on my Mac?

In the past it was helpful to reinstall the system if you wanted to correct some Mac problems, but today this solution doesn’t make as much sense. 

Since macOS Big Sur, macOS has its home on its own volume, which is both read-only and cryptographically signed and sealed (referred to as a Sealed System Volume). This seal is stored either in the T2 chip of the newer Intel Macs or in the Secure Enclave of the Apple M1/M2.

Each component of the system is signed in hierarchical order, and any change to a component would also invalidate the seal that represents the top level. For further security, these Macs also do not start directly from the system volume, but from a snapshot of the system. And snapshots cannot be changed, even by the system itself. So macOS itself cannot be changed by any software that you install as a user.

Full article is here.

Ironically enough, except for the part you quoted, that article is pretty good.

In theory, you could erase just the data volume and leave the system volume intact. However, the data volume still contains lots of system software, the overall structure of the file system, and all of the databases and persistence files that define the computer's configuration.

A "clean install" or a "factory-fresh" install is actually more useful these days than ever. Lots of 3rd party software is very difficult to uninstall. In many cases, the easiest way to uninstall it is to erase the hard drive and reinstall the operating system. The only trick is to avoid restoring all of the data. You can restore your user files and user accounts, but that's all. Don't restore any apps, software, or "other files". That would restore the software you were trying to remove in the first place.

Cartoonguy wrote:

Yes, everything you describe makes sense to me, which is why I wondered about the "no need to clean install" assertion.

I think that is just a case of some mass media tech "journalist" copying and pasting information from elsewhere that is mostly pretty good, but not understanding how the operating system actually works.

Yes. The operating system is on a cryptographically seal volume mounted via read-only local snapshot. There is no reason to ever need to erase it. But much of the rest of the operating system is on the data volume. That is the part that does need to be erased sometimes. There is no facility to erase just one of those volumes.

In theory, that is a feature Apple could implement, but they have no incentive to do that. Pretty much the only reason to do this kind of erase is due to the installation of low-quality 3rd party system modification software. Apple likes to discourage this kind of software anyway, so if people want to stray from the App Store, let them suffer.

My specific problem is related to external drives ejecting randomly very frequently.

Can you quantify that? Every night? Once a week? Once a month. I get spontaneous ejects about once every two weeks. It's not that big of a problem.

It happens any time, often at night, so when I go to the Mac in the morning, I see the warning messages about not ejecting properly, but the drives have often reconnected already by themselves, but not always.

Here's some more info about what I have connected and how:

Lacie 3TB HDD - USB3 through USB3 hub

• 2TB HDD drive in generic enclosure - USB3 through USB3 hub

• Lacie 3TB HDD used as Time Machine - USB3 direct to Mac

• Lacie 4TB HDD - USBC direct to Mac

• 2TB SSD drive (Kingston NV1 2TB M.2 2280 NVMe PCIe Internal SSD in a SABRENT USB 3.2 Type-C Enclosure for M.2 PCIe NVMe and SATA SSDs

That is a lot of drives. I usually have only one external mounted. I get a spontaneous eject overnight once every 14 days. If I do the math, you should get one once every 3 days. Sound about right?

All of them have ejected by themselves at one time or another, but I find the Time Machine and the SSD ejects more than others, so clearly not a USB hub issue. I have had to reformat the SSD because it got corrupted, presumably due to all this ejecting, but who knows.

Even after a fresh reformat of the SSD, I am still having a problem. I tried to copy back my 375gb Photos library and it said "preparing to copy" for hours. Would not copy, but other files did just fine. Not sure why, but it is large, so maybe there was an issue with the size, but it should still copy. I checked Disk Utility to see if a Disk First Aid would tell me anything. When I tried to repair it, I got an error message.

This, just after I had done a reformat. Previous to this the drive failed to mount and I had to reformat and copy back all the data.

So could this SSD drive actually be faulty?

Define "faulty". All of that SSD is PC tech. In theory, it should work. But if theory were identical to practice, we wouldn't have two words for them, would we?

But if it is, why are other drives ejecting? Can one faulty drive (if it is) mounted on the system cause other drives to behave badly?

That is the nature of USB. It is subject to random bus resets. That's why I recommend Thunderbolt instead, especially when people are trying to boot from the external. You aren't trying to boot, but you do have lots of fast SSD hardware hooked up to that flaky USB bus. I realize they keep publishing new USB specs with ever higher theoretical speeds. But it's still the same old USB. There is a reason why some people pay more for Thunderbolt.

I note that when I changed computers from my Imac to my Mac Studio, the only new drive was the SSD, so I wonder.

I don't wonder. Seems pretty straightforward. It seems like a good chance the Time Machine volume might be on the same internal USB bus as the SSD. That might explain why it gets ejected too.

As I am typing this, I did manage to get my Photos library to start copying to the SSD drive (after a restart) and it seemed to be going smoothly, but then the SSD ejected by itself and got this error message.

So I am baffled, but leaning towards the drive itself being faulty. Not sure what else it could be.

I think it's just a case of flaky USB protocol + flaky PC tech + multiple points of failure. That's 14 TB of storage, not counting the internal. Do you really need 14+ TB online 24x7? You mentioned copying 375GB of photos data. Did you buy an internal hard drive that was too small?

I really don't see anything unreasonable. If you had described all of this at first, I would have assumed you would get spontaneous hard drive ejects about once every 3 days. I see these kinds of complaints pretty often from people who have slowly crept, drive by drive, from consumer-scale storage into professional scale. Time to limber up that credit card.

What a clean install fixes are various third party system modifications. Your computer was configured for optimal performance, reliability, and security the day you opened the box. All changes will reduce those factors to some degree. If it gets bad enough to interfere with your normal usage, then a clean install will fix it. If you put those system modifications back, then you will have accomplished nothing beyond wasting your time.

Well, you specifically asked about a clean install, so that is what I addressed. If you are having a specific problem, it is much better to lead with that instead of waiting until you are already deep into a rabbit hole. But it sounds like you haven’t gone too far in, so you are doing pretty good.

Usually a problem with ejecting drives is going to be a hardware problem. But maybe you have some virtual machine that is trying to take over the external drive. I don’t know. Maybe you have a flaky hub. I don’t know. Usually, when you upgrade the computer, it will be best to upgrade any software and hardware along with it. It can sometimes be like putting old wine into new bottles. Maybe the simplest explanation is the answer. Maybe there is some kind of hardware failure. If you can easily reproduce it, take the computer, and the external drives to an Apple Store and reproduce it at the Genius Bar.

Cartoonguy wrote:

I will unplug the other two to see if it helps. I would think I should be able to have two external drives and a Time Machine back up drive.

It sounds like it is the SSD that is the most problematic, so that might not help.

Your comments about the USB bus sound like what I was suspecting. That the problem is related to everything on the bus and so random ejects might be caused by one issue impacting all drives on the bus. That makes sense.

I have had multiple drives connected to my previous older iMac via both USB and older Thunderbolt RAID and rarely, if ever, have I had this kind of ejecting drive issue, so it is surprising to me that you say it's pretty common for you. Does it concern you? Does random ejecting and the associated warnings about ejecting properly mean that the drives could be getting corrupting every time it happens?

It doesn't bother me. It is one of my Time Machine volumes. It is an older, Thunderbolt 2 device, on its 3rd internal drive, connected to an M1 MBP. I think it's doing pretty good.

It could get corrupted, but it's just Time Machine. I can erase and reformat if I had to. It's not a big deal.

It's happened three times today on the SSD while I was attempting to copy files over.

It is one thing to have a drive get disconnected overnight, during various wake/sleep cycles. A drive should never disconnect while you are actively using it.

What does it mean that Disk Repair will not work on the SSD, even after a fresh reformat?

Who said that? Disk Repair isn't what people think it means. But this is one of the few cases where it could be helpful. All it does is repair a corrupted file system. That shouldn't ever happen on a modern APFS file system anyway. And modern Disk Utility doesn't have a great track record actually making said repairs.

But Disk Utility can never repair a drive that has physically failed. Or in your case, if it's just flaky, you can't fix that with Disk Utility. If it did remount in read-only mode or something like that, then Disk Repair might help. But it should be a moot point. If you are getting three disconnects while using the drive, you should consider any data on the drive to be hopelessly corrupt. Hopefully you have another copy of that Photos database.

Why is it ejecting while files are being written to it?

It's junk.

It also ejects sometimes at night when no files are being written. So that's what I mean by the drive maybe being "faulty". This is not normal experience for me in all the years I have been computing, so could it be a hardware failure?

It's hard to say. It's 2022. Where did you buy this thing? Amazon? How do you know it is really Kingston? Sabrent is a well-known name and not known to be junk. But it also is known for making cheap PC hardware. So far it sounds like you've put way more time into this thing that it was ever worth.

Are some SSD drives not actually Mac compatible?

Sure. There are always stories of devices with flaky firmware that doesn't work great on a Mac. Of course, you are using this in a USB enclosure, so that wouldn't apply. The question is how well the SSD works with the enclosure. And then how well does the enclosure work with the Mac. Something like a cheap M.2 enclosure probably hasn't ever been tested on a Mac. That is, until you tested it. Doesn't sound like it passed.

I've never heard of that as I assume you just format for Mac and use it, like any HDD, but should I be avoiding anything but SSD drives designed for Mac specifically? Does that even exist? Anyway, that's what I mean by my question about it being faulty, because this behaviour is entirely new to me since using Macs for many years.

It's been that way as far as I can remember, maybe 30+ years. To be clear, I'm not saying that it flat out won't work. I'm just saying that you are taking a risk using PC hardware. Maybe it works. Maybe it doesn't. A Mac user trying PC hardware has to be ready to return it or trash it if it proves to be unworkable. Over time, you'll get a better feel of which devices you can reliably use and which ones are a waste of time. We often recommend OWC just because they are a Mac-only shop and you can always expect their products to be tested on Macs. You can buy products from elsewhere, but you will be the one doing the tests. On a place like Newegg, you can read the reviews and see if Mac users seem to have good luck. But elsewhere, Amazon, etc. - you're on your own.

I assume you just mean the system drive).

The startup "drive" now consists of a System Volume and Data volume. The System Volume is sealed and mounted read only. There would be nothing there that could possibly be altered.

The only equivalent to erasing and reinstalling would be use Erase all Content and Settings, then migrate from your backup, not migrating the apps and settings. I have no idea if that comports to your definition of a "clean install."

Try stopping them from sleeping. In Terminal,

sudo pmset disksleep 0

Probably no point in erasing the system volume, but any stuff you added would be on the Data volume, so that is what you need to "clean."

I don't know what you mean by cleaning. You used the term, "clean," in the title of the post. You used the term asking if it was appropriate given the new sealed snapshot startup volume. Whatever you consider "clean," it doesn't apply to the sealed snapshot.

The only thing it would possibly apply to would be the Data volume.