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benji888

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Sep 27, 2006
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I took a PCIe SSD out of a late 2013 iMac I put in an OWC external case to use with my Mac mini M2, (its an Aura Pro X2 480GB), however I forgot to erase it before taking it out of the iMac, now it won’t mount, so I’m trying to erase but it’s stuck “deleting volume”, I don’t think it’s working and I don’t want to wear the SSD by leaving going for hours. …I did try clicking on “mount/unmount” first but it didn’t do anything.
 

benji888

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Sep 27, 2006
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Connect the external drive back to the iMac and erase from there? 🤷‍♂️
um, yeah, that should work, except, I took all my drive upgrades out of the iMac and put back the original HDD, erased before putting it back, so I’ll have to do an Internet based restore first.
 
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Nermal

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A workaround I've used in the past, if you're just trying to erase it, is to unmount it then start zeroing it out from Terminal:

sudo dd if=/dev/zero of=/dev/rdiskx bs=1m (where x is the ID for the disk, shown in Disk Utility).

Let it run for just a couple of seconds then abort with Ctrl-C. You only need to wipe out the partition table, not the whole thing. Disk Utility should then be able to set up a fresh partition table and hopefully won't freeze.
 

benji888

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Sep 27, 2006
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so I finally got macOS Catalina on the iMac and erased the drive. Now it won't mount via my TB4
OWC dock, says USB devices disabled until one that requires too much power is disconnected. (???) Yah, that makes no sense. I can unplug everything, connect just the ssd to the dock and it won't mount. So, it only works if connected directly to the Mac mini. OK, why now? IDK, it would light up before but couldn't access it, now it won't even light up when connected to the dock. It's a full TB4 dock, there shouldn't be an issue connecting an SSD to it. It's an OWC Envoy Pro 1A enclosure made specifically for this type of SSD, the SSD is an OWC Aura Pro X2 480GB (NVMe SSD) PCIe 3.0 x4, made for a specific line of Macs made from late 2013 - 2019. Neither the SSD nor the enclosure have any special power requirements and should work with the USB 3.2 standard connection.
 

benji888

macrumors 68000
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Sep 27, 2006
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so I finally got macOS Catalina on the iMac and erased the drive. Now it won't mount via my TB4
OWC dock, says USB devices disabled until one that requires too much power is disconnected. (???) Yah, that makes no sense. I can unplug everything, connect just the ssd to the dock and it won't mount. So, it only works if connected directly to the Mac mini. OK, why now? IDK, it would light up before but couldn't access it, now it won't even light up when connected to the dock. It's a full TB4 dock, there shouldn't be an issue connecting an SSD to it. It's an OWC Envoy Pro 1A enclosure made specifically for this type of SSD, the SSD is an OWC Aura Pro X2 480GB (NVMe SSD) PCIe 3.0 x4, made for a specific line of Macs made from late 2013 - 2019. Neither the SSD nor the enclosure have any special power requirements and should work with the USB 3.2 standard connection.
...it gets warm when connected to the dock even though it does not mount nor light up. (?)
 

warpmoon

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Jun 7, 2009
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Neither the SSD nor the enclosure have any special power requirements and should work with the USB 3.2 standard connection.
Your iMac has USB 3 ports which cap out at 4.5W. Your NVMe drive is listed as pulling at most 5.7W, plus whatever the enclosure uses.

The enclosure is listed as being bus powered because it's made for USB 3.2 ports and has a USB-C connector, likely because that standard supports 7.5W or 15W (without accounting for PD-features) which would be sufficient but it doesn't leave a lot of juice left over for other things.
 

benji888

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Sep 27, 2006
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Your iMac has USB 3 ports which cap out at 4.5W. Your NVMe drive is listed as pulling at most 5.7W, plus whatever the enclosure uses.

The enclosure is listed as being bus powered because it's made for USB 3.2 ports and has a USB-C connector, likely because that standard supports 7.5W or 15W (without accounting for PD-features) which would be sufficient but it doesn't leave a lot of juice left over for other things.
EDIT: I just reread this, Actually, you're assuming a lot of things.

1) The enclosure has a micro USB 3.2 connector, not C, all of your power measurements are from standard NVMe and USB C, this is not any of that. This is an apple proprietary NVMe, it does not fit in a standard NVMe drive enclosure:
... It's an OWC Envoy Pro 1A enclosure made specifically for this type of SSD, the SSD is an OWC Aura Pro X2 480GB (NVMe SSD) PCIe 3.0 x4, made for a specific line of Macs made from late 2013 - 2019. Neither the SSD nor the enclosure have any special power requirements and should work with the USB 3.2 standard connection.
specs here: https://eshop.macsales.com/item/OWC/MAU3ENP1AW/#specs

Nothing in the specs about any special power requirements, bus powered, yes, but it uses a standard USB 3.2 micro/A connector (cable included), WHICH I connect to the iMac and was able to access and erase the drive.

2) I am now trying to use it with my M2 Mac mini, it will work fine in a USB A port on the Mac, it will not work connected to the OWC TB4 dock in one of the USB 3.2/A ports, which should not be an issue, I am wondering if something is wrong with the dock, it's power supply or the TB4 cable, but, it's not like I plug/unplug or move the device, it stays put. IDK, I don't have issue with other devices. ...I have had drives eject themselves when Mac sleeps, but, I think that's due to the M2 Mac's deep sleep mode, not sure how to change this.
 
Last edited:

warpmoon

macrumors newbie
Jun 7, 2009
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EDIT: I just reread this, Actually, you're assuming a lot of things.

1) The enclosure has a micro USB 3.2 connector, not C, all of your power measurements are from standard NVMe and USB C, this is not any of that. This is an apple proprietary NVMe, it does not fit in a standard NVMe drive enclosure:

specs here: https://eshop.macsales.com/item/OWC/MAU3ENP1AW/#specs

Nothing in the specs about any special power requirements, bus powered, yes, but it uses a standard USB 3.2 micro/A connector (cable included), WHICH I connect to the iMac and was able to access and erase the drive.

2) I am now trying to use it with my M2 Mac mini, it will work fine in a USB A port on the Mac, it will not work connected to the OWC TB4 dock in one of the USB 3.2/A ports, which should not be an issue, I am wondering if something is wrong with the dock, it's power supply or the TB4 cable, but, it's not like I plug/unplug or move the device, it stays put. IDK, I don't have issue with other devices. ...I have had drives eject themselves when Mac sleeps, but, I think that's due to the M2 Mac's deep sleep mode, not sure how to change this.
Perhaps I misunderstood your post, I found it difficult to follow.
You only mention a single type of NVMe, the OWC Aura Pro X2, that's not a proprietary Apple drive. The tech specs of that specific product lists 5.7W as max power draw. Your iMacs ports do not support that since they are USB 3.0, which at it's core maxes out at 4.5W unless certain optional features are included. The fact that it sort of worked is interesting, but by it's very nature unreliable since certain operations can have drive need more power than the port can provide.

Me mentioning USB-C was unfortunate since the port type doesn't actually play into the matter, the USB generation is the primary factor. You didn't link any product in the OP so I searched for "Envoy Pro" and found Envoy Pro Ekektron which does in fact have a USB-C.

You don't say what TB4 dock you have so it's likely going to be difficult for anyone to comment on that. But I can say that having power delivery issues with external docks is a recurring issue for many. The overall reliability of externally attached storage devices through a dock is hit or miss.
 
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