Late 2015 iMac Thunderbolt 2 ports not working

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Level 1

9 points

Late 2015 iMac Thunderbolt 2 ports not working

Hello Apple discussion community,

I need your help on my iMac,

I have a late 2015 iMac with thunderbolt 2 ports, and when I use a (TB3) thunderbolt 3 dock or thunderbolt 3 hard drive via Apple's TB3 to TB2 adapter it does not work. However the TB3 to TB2 adapter works fine with the same TB3 dock & TB3 hard drive on another iMac late 2013 which has thunderbolt 1 ports.

I learned from this video on YouTube the problem is incorrect Thunderbolt firmware version-

How to Fix Thunderbolt external hard drive not detected Complete Guide | Apple and Lacie

https://www.youtube.com/watch?v=ikBTrqoqjDg&ab_channel=AVMEVideos

However following his instructions did not work for me, he ran Yosimete MacOS from an external flash drive to install the apple thunderbolt firmware v.1 to get it to work with his Lacie hard drive.

Thunderbolt Firmware Update v1.0 (this is what he used)

https://support.apple.com/kb/dl1407?locale=en_US

I realized from his video that his iMac is older than mine, so I could not run Yosimete MacOS, however I could run El Capitan MacOS from flash drive. El Capitan does not allow me to install that thunderbolt firmware, even if I tried v1.1 or v.1.2.

Below are the items used-

Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter

https://www.apple.com/shop/product/MMEL2AM/A/thunderbolt-3-usb-c-to-thunderbolt-2-adapter

Apple Thunderbolt Cable (2.0 m) - White (this is Thunderbolt 2 cable)

https://www.apple.com/shop/product/MD861LL/A/apple-thunderbolt-cable-20-m

CalDigit TS3 Plus Thunderbolt 3 Dock

https://www.amazon.com/gp/product/B07CZPV8DF/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

OWC TB3 Hard Drives

https://eshop.macsales.com/shop/thunderbay-flex-8/thunderbolt-3

Screenshots:

My iMac late 2015-

My iMac L2015 TB2 firmware and shows TB2 not connected, when dock or hard drive is connected.

An iMac Late 2013 that works with TB1-

TB1 when connected with TB3 dock via adapter-

Posted on Oct 16, 2020 1:19 PM

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Answer 1

karina184

Community Specialist

Oct 21, 2020 6:26 AM in response to tiger1442

Hi tiger1442,

It sounds like not getting any connectivity via those ports. To start with the basics, do any accessories work when connected to them?

If nothing works via those ports, we recommend performing an SMC reset as shown here: How to reset the SMC of your Mac

If the behavior continues after the reset, we next recommend all of the steps here: If a USB device doesn’t work with Mac

We hope that helps.

Take care.

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Answer 2

tiger1442 Author

Level 1

9 points

Jan 30, 2021 12:29 PM in response to Mikerider

Hi, thanks for sharing your research on an external powered nvme thunderbolt storage solution that works on the late 2015 iMac. I am glad to hear you found Netstor powered tb3/nvme enclosure. Can you please provide a link on where it can be purchased? In addition I found a powered nvme TB3 drive on Amazonhttps://www.amazon.com/gp/product/B08L952WCB/ref=ox_sc_saved_title_3?smid=A238Y4P9B8CANA&psc=1

haven't purchased it yet, but this powered nvme tb3 enclosure may work since Netstor worked for you with the tb3/tb2 adapter.

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Answer 3

tiger1442 Author

Level 1

9 points

Feb 13, 2021 6:46 AM in response to Mikerider

Hi Mikerider,

I just received the Trebleet and added 2TB NVME SSD. I tried it on my late 2015 iMac and it does not work with the tb3/tb2 adapter. I tried Trebleet on 2018 Mac book Pro on TB3 and it works fine. So it's not the Trebleet, the problem is the late 2015 iMac.

I have updated the iMac to Mac OS 11.2.1 Big Sur and tried it again, still does not work. Perhaps you have a different late iMac 2015 that worked with Netstor? My about iMac screenshot is shown below, do you have the same TB2 firmware?

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Answer 4

Feb 14, 2021 12:59 PM in response to tiger1442

Hi there, what a pity that didn't just work!

I'm no expert and there's not so much to go on out there, so only posting what I found to work.

one other suggestion to try was just something I came across when I thought I might be getting a dock that might not be officially supported - perhaps look into this hack before your next move https://9to5mac.com/2016/11/21/tb3-enabler-enable-unsupported-thunderbolt-3-devices-hack-macbook-pro/

Looks like you have a slightly higher spec iMac which I would have though should work in your favour. I'm still on Catalina though, and Thunderbolt firmware is at 27.4

Posting my spec for you here. (ps I disconnected the fan altogether on the Netstor and seems fine with 2x Sabrent Rocket 4.0 plus 1tb drives, and monitoring temp with iStat menu. they seem to hit around 32 degree max. often less than the internal ssd.

Wishing you luck!

Mike

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Answer 5

tiger1442 Author

Level 1

9 points

Oct 21, 2020 7:11 AM in response to karina184

Hi karina184,

Thank you for taking the time to read and reply, greatly appreciated.

Yes this accessory (Thunderbolt to HDMI Adapter)

works with the ports- https://www.amazon.com/gp/product/B01N6M2VN4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

when hooked up to an HDMI monitor or TV.

We have these same iMacs in our school along with MacOS Catalina. I tried it on 5 of these same late 2015 iMacs at school and all of them do not work with the TB3 hard drives or dock. However it works with the Thunderbolt to HDMI adapter mentioned above.

I can try the SMC reset you suggested and see if it works, I will let you know.

Thanks again.

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Answer 6

Leanne_68

Community Specialist

Oct 21, 2020 11:12 AM in response to tiger1442

Tiger1442, thank you for confirming that information and trying with multiple devices. If other devices are working with that port, we recommend contacting the accessory's manufacturer to confirm compatibility. We appreciate your time, patience, and understanding.

Take care.

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Answer 7

tiger1442 Author

Level 1

9 points

Oct 21, 2020 2:19 PM in response to Leanne_68

Hi Leanne_68,

My OWC thunderbolt 3 (TB3) hard drives and the Caldigit TB3 dock work fine on another Macbook Pro (2017) that I have running Mac OS Catalina 10.15.7 on it's TB3 ports. The same two accessories work fine even on an older iMac late 2013 with TB1 ports via the apple TB3 to TB2/TB1 adapter as shown on the screenshot I originally posted above. So there is nothing wrong with the accessories since it works on two different model Macs.

However I can try contacting OWC when I get back to my office where I have this iMac.

Furthermore, I have a question for the Apple community. Does anyone have a late 2015 iMac with thunderbolt 2 ports and TB2 hard drives that work? If yes please mention your thunderbolt firmware version or add a screenshot along with what Mac OS version you have running on your iMac. This question will help determine if this specific late 2015 iMac TB2 problem is widespread.

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Answer 8

Drakedk

Level 1

4 points

Nov 30, 2020 1:51 PM in response to tiger1442

Hi,

I have the exact same issue myself. I have the same imac, late 2015, running Catalina 10.15.7

I have an external thunderbolt drive that will not mount to my iMac. This drive does mount via thunderbolt to my MacBook Pro running 10.10.5.

This is not a Lacie issue. This is an Apple issue. I need help to get this drive mounted. Thank you.

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Answer 9

Dec 16, 2020 7:04 PM in response to tiger1442

I am experiencing this issue as well, I bought a brand new LaCie SSD, TB2 to TB2 (male-male) cable, and a TB2 to TB3 adapter from Apple. I have a 15" and a 13" mid 2015 MBP and the drive does not work on either. I have tried everything on the "if a USB device doesn’t work with Mac" guide. The drive works when plugged into USB 3.0 ports but not TB2. I have thunderbolt bus firmware 27.1. Really disappointed that Apple doesn't seem to care about supporting TB2.

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Answer 10

Jan 28, 2021 4:02 PM in response to alexanderme

Does your lacie ssd have its own power - or is it bus powered (ie with the one usbC type data cable ?

the apple TB3/TB2 adapter will send data via the TB2 cable but won't power up devices that are not themselves already powered.

One option is to find a powered dock. Connect that to the mac via the TB3 /tb2 adapter - and connect your Lacie to the dock, which should power it up.

-

I was looking into this option myself to add external nvme ssd enclosure via thunderbolt to late 2015 imac. Problem is most enclosures (tb3 or usbC) are not powered, just bus powered. So i was about to go the dock route described above.

However I found Netstor do a powered tb3 / nvme enclosure. So this is working great with the tb3/tb2 adapter and tb2 cable. Getting read/write speeds 1250/1250mbs

Took a bit of research. Hope this helps someone.

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Answer 11

Jan 30, 2021 1:08 PM in response to tiger1442

Hi. That Trebleet looks like it would work in theory. I can't post link to the item I purchased as was a used eBay unit here in UK.

But a quick search for example

https://www.bhphotovideo.com/c/product/1381233-REG/dynapower_usa_netstor_na611tb3_thunderbolt_3.html

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Answer 12

tiger1442 Author

Level 1

9 points

Jan 30, 2021 3:53 PM in response to Mikerider

Nice to know B&H carries the Netstor, B&H is in my vicinty here at the USA. The difference I see between Netstor and Trebleet is that Netstor has a variable speed fan and Trebleet does not and of course the price. I may choose the Trebleet as I don't need to run it for a long time so I should not run into heat issues. In addition if it does not work I'll return it. I'll post my results when I try it out. If anyone is interested here's more information on the Trebleet enclosure- https://www.trebleet.com/product-page/thunderbolt-3-two-slot-m-2-nvme-ssd-storage

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Late 2015 iMac Thunderbolt 2 ports not working

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