Mac Pro 2023 will not boot with PCIe SSD installed.

Some progress has been made. While for some reason, the new and unformatted OWC 8M2 drive was still causing this issue (it could be due to needing an additional power cable/supply), I tried a new and unformatted OWC 4M2 drive and it worked.

I am currently back to work using the M2 Mac Pro and a new OWC 4M2 PCIe SSD to store my active audio projects.

In talking with OWC, it seems that the new Mac Pro might not like external PCIe drives that are formatted to anything other than APFS Volume • APFS.

Hopefully Apple can release an update that makes the M2 Mac Pro work with a wider variety of external drives in terms of how they are formatted.

Hi David,

Thanks for your contributions to this thread. It sounds like we have a lot of similarities in how we use the Mac Pro and OWC SSDs dedicated for audio.

Because it all just worked flawlessly on my 2019 Mac Pro, I've never dug this deep into some of the specs in SoftRAID, but here is a screen shot of some specs from the 42M that is currently working in slot #6 of my 2023 Mac Pro.

I don't have it set up as a RAID, it's just used as one big drive. I just ordered a 2nd 42M for my backup drive so we'll see if that works, or causes issues. It should be here Monday or Tuesday.

I also have three RME PCIe cards in slots 1, 2, & 3 which seem to be fine. Even with JUST the new and unformatted 82M in the new Mac Pro and nothing else, I couldn't get the 2023 Mac Pro to boot. Same with my previously working and formatted 42M drives that were in my 2019 Mac Pro.

The only thing that is working so far is the 42M that was never before formatted and arrived from OWC last week. I attached a screenshot and it says something about 64KB.

It's weird that your overnighted 42M didn't work. The plot thickens.

You'll also see in my screenshot that my older spinning HDDs which are in an OWC Thunderbay 8 are working just fine. They're 3.5" HDDs formatted to SATA External Physical Volume • Mac OS Extended (Journaled).

These are just for older/finished projects and not something I normally keep mounted, but it's interesting that those are just fine. Normally I keep that unit turned OFF because of fan noise and I don't need that data often.

The issue seems to be related to PCIe SSDs that are formatted and configured a certain way that the new Mac Pro 2023 is not happy with, but the 2019 Mac Pro wasn't happy with.

I was also thinking I should have went with the Mac Studio and dealt with the external PCIe to Thunderbolt chassis but without a Mac Studio here, it's hard to know if that would be any different because even when I put my older 42M (which was fine in the 2019 Mac Pro) in my Sonnet Echo Express SE I chassis, it brings the Mac Pro to a grinding halt. It won't boot if it's connected, and if I connect it while it's booted, it freezes instantly.

I also couldn't get in via Recovery Mode.

It's weird that your overnighted 42M didn't work. The plot thickens. Did you format it as APFS? I'll attach a screenshot of the settings that are currently working in my 2023 Mac Pro.

After a half day of things not working, I tried the newly unformatted 4M2 for sh*ts & giggles not expecting anything and of course, that was the only one that worked and allowed the Mac Pro to boot up.

Yes, sorry for the blurry screenshot but I'm now just using a small old TV for that computer since I'm now using the 2023 Mac Pro in my main setup.

Attached is a picture of my older 4M2 that worked in my 2019 Mac Pro, but not only didn't work in the 2023 Mac Pro, prevents it from even booting up. I tried putting it in a Sonnet Echo Express SE I but even that prevents it from booting up and if I connect the Sonnet Echo Express SE I (with this SSD in it), the 2023 Mac Pro freezes instantly.

@SoftRAIDSupport

Thanks for the reply. Would this be true for brand new "Out of the Box" 42M drives that have never been formatted yet?

The problem is that since the Mac Pro 2023 won't boot at all with these 2TB drives inserted, I would have to use my old 2010 Mac Pro to do the formatting which I can do but...

If you didn't see my other messages. My 4TB 4M2 is for some reason working on "out of the box" in my 2023 Mac Pro. My brand new unformatted 2TB 8M2 and 4M2 would not allow the 2023 Mac Pro to boot up at all, which makes doing any formatting or SoftRAID changes impossible to do.

Attached is a screen shot of the 4TB 4M2 that out of the new box allowed the Mac Pro M2 to boot up and then I formatted and named it and has been fine since Friday.

I just tried another 2TB 4M2 out of the box (while the working 4TB remained in the Mac Pro) and it DID NOT allow the Mac Pro M2 to boot up.

I think I have logs from pressing SHIFT CONTROL OPTION COMMAND PERIOD KEY during the failed boots but I don't know where they are stored. I can find them you can point me to where they are.

MacOS 13.4 (22F2073)

I have not had a single issue with the 4TB 4M2 that I installed as a last resort on Friday after just about giving up. It was meant to be my backup drive to my smaller 2TB 4M2 but so far it's the only PCIe SSD I've had that will allow the Mac Pro to boot up. Zero issues. Many restarts for other misc troubleshooting.

I will keep the SoftRAID software uninstalled for now since I don't seem to need those features. I didn't know it wasn't required.

Attached are some images that may be of use from Disk Utility.

Thanks for the report. That's why I posted here, to see if anybody else has the issue. I think it's going to be across all new Mac Pros.

What's interesting is that I bought a new OWC 8M2 that I was planning to use with this 2023 Mac Pro and even unformatted, the 2023 Mac Pro would not boot with it. It was never used or formatted. OWC suspected it could be because I didn't have additional power connected to the drive but I didn't get that far and just returned it. I didn't care for the fan noise I was hearing while it was attempting to boot up.

It would also not boot with my previously formatted 4M2 drives that worked just fine in my 2019 Mac Pro. They were formatted to MacOS Extended (Journaled).

The Mac Pro boots just fine with no PCIe cards and even with my 3 different RME Audio PCIe cards.

As a last resort, I tried my brand new unformatted OWC 4M2 which I was planning to use as the backup drive and for whatever reason, that one worked.

I just did a fairly full day of work without any issues.

Apple and OWC are aware of my reports, but we'll see if anything comes from it.