My MacBook Pro can’t find startup disk

Depending on it's age and the type of HDD or SSD that is installed (Serial ATA), it could be that your particular MacBook model/year (which you don't mention) has a bad internal SATA 2 cable. This is the connector that the HDD/SSD plugs into on one end...the other end is connected to the Mac's logic board. These cables can sometimes go bad and the symptoms would be similar to what you are seeing, especially when different HDDs/SSDs are connected and exhibiting similar symptoms.

Since Apple will not service an old MacBook (past a certain age) as you've stated, the repair will have to be third-party or self-repair.

You may want to research and Google "macbook bad sata cable". This will give you an idea of what may be going on with your MacBook. You may be able to repair it yourself but do the research first. I can only provide you what to research and search for on Google. Direct links to various third-party websites are mostly not allowed here.

frankynstein wrote:

I would take it to a third party technician (I know apple won’t touch it what with the age of it and my upgrades) but I currently have covid, so if anyone has any suggestions I can try in the meantime while I’m housebound, I’d be grateful!

You already got a response about the SATA cable. I've heard that Apple may even provide it as a courtesy fix well out of warranty. I got mine in 2015 (manufacturing date was in 2014) and when I saw what it had, it was one of the later versions that had thicker materials.

But I can comment on user upgrades and how that affects how Apple serviced my mid-2012 Unibody. It's what I'm using for this response. My current setup is has a 1 TB WD Blue SSD and 16 GB of Silicon Power branded memory that cost me $40 but right now Amazon has it for $20. It got cheap really quickly.

https://www.amazon.com/gp/product/B07L8C37DH/

I had a battery problem last year. All of a sudden it no longer worked and I couldn't even power it on with just external power like used to be possible with older Macs, which I tried out before. So I got an appointment at an Apple Store, although I put the factory 4 GB memory back in just in case, but had to have a working drive so I left that in. It did start working again when I got to the store when I waited for a tech to look at it. However, the battery was saying it needed to be serviced and it was reporting about 63% battery health. I didn't have any problem getting a battery replacement. The service order did note that the keyboard had worn keys but the case was otherwise pristine. I did get a call the next day or so about my order. When I called back a tech said that the drive diagnostics "failed" and asked if I wanted to replace the drive. Apparently it failed because it was aftermarket. I declined and they did the service anyways.

I can also comment on what I found when I tried putting the memory back in. They had attached some sort of graphite thermal pad that was placed on the cover using a pressure sensitive adhesive. It was in contact with the memory. I kind of left it in place but only after trying to remove a few of the layers.

As I recall when I self-refurbed my MacBook Pro (13" Late 2011), the SATA cable is fairly simple to swap out. This would be the place to start (cheap and easy to do) to eliminate that possibly "weak/broken link" in the chain. Good luck to you.

SergZak wrote:

As I recall when I self-refurbed my MacBook Pro (13" Late 2011), the SATA cable is fairly simple to swap out. This would be the place to start (cheap and easy to do) to eliminate that possibly "weak/broken link" in the chain. Good luck to you.

Like I said previously, I heard Apple has replaced it as a courtesy fix, but I suppose age might be an issue. The mid-2012 Core i5 was in production until 2016 and it's been almost 7 years. There's also the issue that even if there's a part that would work, there might be limitations on what devices are eligible for service based on when they were discontinued. Like the battery fix for any 13" Unibody where the same part is available, but probably not for something like a 2009 MBP.

The biggest issue with those aftermarket SATA connectors is that some of them are built to the same standard as the original version but then they're sold as equivalent to the latest Apple part numbers.

My replies are based on the assumption (which I feel is a good one) that Apple will not even care to look at the device due to it's age...and may very well look at the individual bringing it in as if they had a third head. I could be wrong but going by what I've heard from others taking "vintage" devices in, it could just be a waste of time, especially seeing that the OP has stated they are house-bound for awhile. A self-fix (if one felt capable enough) would be worth it to me, personally.

Even if the third-party part were same spec as the original, replacing it would at least rule out that particular known bad link. How long the part lasts wouldn't really be an issue...if the part replaced fixes the problem and the fix is simple enough for the end-user to accomplish, simply replacing the part again when/if it failed again would always be an option.

SergZak wrote:

My replies are based on the assumption (which I feel is a good one) that Apple will not even care to look at the device due to it's age...and may very well look at the individual bringing it in as if they had a third head. I could be wrong but going by what I've heard from others taking "vintage" devices in, it could just be a waste of time, especially seeing that the OP has stated they are house-bound for awhile. A self-fix (if one felt capable enough) would be worth it to me, personally.

Even if the third-party part were same spec as the original, replacing it would at least rule out that particular known bad link. How long the part lasts wouldn't really be an issue...if the part replaced fixes the problem and the fix is simple enough for the end-user to accomplish, simply replacing the part again when/if it failed again would always be an option.

I was rather surprised that my mid-2012 MBP could be serviced at an Apple Store. It was past the 5 year window but I remember the old rules were that "vintage" was up to 7 where Apple said that Mac service could be done in California, but only at AASPs. They got rid of that rule and allowed service at Apple Stores or AASPs. But then there was the new 10 year battery replacement service "Maybe" policy.

But then again, it might be worth a try. At the very least a diagnosis should be free even if they're not willing to perform a fix.

My only recommendation when bringing an old Mac would be to be careful about any aftermarket memory of drive replacement. In my case they asked to replace a perfectly functional SATA SSD because their diagnostics said it was "bad" (i.e. not OEM).

frankynstein wrote:

The SATA cable was my initial guess, but when the original HDD worked with it I thought it must be the SSD.

The SATA Cable had such a high rate of failure that Apple would replace it even if the user never mentioned a problem with the drive. That is the first & only time I have ever seen Apple proactively replace a part which did not show any symptoms.

An SSD transfers much more data at a much higher transfer rate, so any minor issues with a cable will have a bigger effect on an SSD than it will on a HD. In fact I've seen multiple different symptoms when the SATA Cable fails.

I’ll look into replacing it and let you know how it goes, thank you!

OWC sells the cable:

https://eshop.macsales.com/search/?q=drive%20cable&filter.catidpath=3406/3410

FYI, Apple did not discontinue the 13" non-Retina model until Oct. 2016 (according to EveryMac.com), so Apple would support those 2016 purchasers for five years which would be until 2021 when the laptop would become "Vintage". "Vintage" products are supported for two more years as long as the necessary parts are still available so theoretically the laptop may be supported until late 2023. People who purchased the laptop in 2012 would have a very good run of support even though OS support stopped with Catalina in 2019.

HWTech wrote:

FYI, Apple did not discontinue the 13" non-Retina model until Oct. 2016 (according to EveryMac.com), so Apple would support those 2016 purchasers for five years which would be until 2021 when the laptop would become "Vintage". "Vintage" products are supported for two more years as long as the necessary parts are still available so theoretically the laptop may be supported until late 2023. People who purchased the laptop in 2012 would have a very good run of support even though OS support stopped with Catalina in 2019.

That was only the mid-2012 13" i5 2.5 though. One database I saw had the 13" i7 2.9 discontinue date as October 2013. So the 7 years was up in 2020 and the 10 year possibility for the battery is almost up.

But the parts may still be available since they're the same as in the i5 2.5, so it might be worth asking nicely.

frankynstein wrote:

Well, I won’t be able to resolve the debate by saying whether Apple would touch my “vintage” device as you call it, as I got a replacement cable delivered, fitted it earlier today and just finished migrating everything from my time machine back up. It seems the cable was definitely the issue. It means I bought a new SSD somewhat unnecessarily, but a spare is always useful. Thanks again SergZak and Y_P_W, I was really at a loss for what to do. All the best!

Good luck with it. The main issue with the "cable/ribbon/tape/connector" was that the original version had really thin insulation, has several bends around tight corners, and would apparently get worn through. For some reason, SSDs were more susceptible to the wear. Apple did eventually create a beefier version (with a new part number printed on the connector), and I've verified that one is in mine. This would be the main reason why it would be preferred - even an OEM salvage part.

https://beetstech.com/blog/prevent-a1278-mid-2012-hard-drive-cable-failure

Not All Cables Created Equal

This MacBook’s cable originally was manufactured with part number 821-1480-A printed on it. Apple offered this particular laptop (order number MD101LL/A) for a whopping four years due to high demand for the Unibody series of notebooks, and at some point wised up and began shipping computers with a revised version of the cable.

The new cables now included a different part number; 821-2049-A and later 821-2480-A. These cables were designed with a thicker plastic film and offered more protection to the wires. We verified the difference while examining some cables we’ve come across in used computers.

This is great news if you were able t get Apple to replace the cable, but new condition cables widely available on the internet may have these part numbers printed on them, but are not the revised cable design.

Manufacturers caught on to the fact that the new part numbers were more sought after and they simply started producing the same old cables with the new part numbers. To date, we’ve never been able to find new condition cables with the improved design. And believe me, we’ve been searching.

Bummer? Yes, but luckily there’s an easy preventative measure that only requires some supplies you probably already have lying around.

All you need to do it yourself is a Phillips PH000 screwdriver and some ESD safe tape. You probably have some common electrical tape which will be perfect for the task.