Thunderbolt ports on 2013 iMac not working

shut down, disconnect all external devices except OEM mouse and keyboard

reset the smc

https://support.apple.com/en-us/HT201295

repeat 2 or 3 times more

boot into safe mode

https://support.apple.com/en-us/HT201262

then reboot normally and connect a single device to verify connectivity.

if not see this article

How to use Apple Hardware Test on your Mac - Apple Support

Please provide more detailed information about your issue and the configuration of your iMac so the iMac community online can do a better job providing assistance. The following information would be helpful:

- What Thunderbolt devices are attached to your iMac? Have you tried moving the Thunderbolt cable to the other Thunderbolt port to see if the issue is resolved?

- Does the Thunderbolt Cable show any signs of damage, excessive bending, fraying, etc? If yes, it should probably be replaced.

- What version of Mac OS X are you running? Did you install any updates just prior to the Thunderbolt ports not working? If updates were installed, which ones? Have you checked for new updates?

- Have you reset NVRAM (In addition to JimmyCMPIT's SMC reset recommendation)? Instruction can be found here:

How to reset NVRAM on your Mac - Apple Support

- Can you see the Thunderbolt cable/devices in the Apple System Report? Do you see just your iMac's two ports, or do you see that there are other devices attached to the ports?

About System Information on your Mac - Apple Support

- Do you have another Thunderbolt cable that you can try? Can you try the Thunderbolt cable and devices on another Mac to help determine where the issue lies?

If you have a backup of your data (I always have at least two backups so I don't lose the only files, family photos and videos, that I truly can't live without) then one last thing to try is to use the macOS Recovery mode to reinstall a fresh copy of the OS. It would be a very rare coincidence for both Thunderbolt ports to fail at the exact same time as an update being installed. I think it's more likely that there was a driver conflict that occurred for some reason.

If you haven't used the recovery mode before here's an Apple article that describes the process. Since you are only reinstalling the OS you won't need to restore your other files, but make sure you have a backup before proceeding just in case.

About macOS Recovery - Apple Support

I have also had this issue occur with my iMac recently -- Late 2013 27-inch 3.5GHz i7..

Thunderbolt ports suddenly "disappeared" a couple of weeks ago. Connected to my iMac were an external hard drive via a Kanex eSATA adapter, and a MOTU AVB audio interface. When I woke the computer from sleep in the morning, there was a message that the hard drive was not ejected properly, and in troubleshooting that error, I discovered that the audio interface was also no longer recognized.

I had tried all of the methods for "fixing" the issue suggested here and on other forums, including:

1 - resetting the SMC (several times)

2 - resetting the NVRAM

3 - swapping cables

4 - swapping ports

5 - disconnecting all peripherals and running the system hardware test, which reported that "may be a problem with your Thunderbolt hardware"

6 - tested both devices connected via USB ports on iMac. Both were recognized.

7- tested both devices connected to a different computer via Thunderbolt. Both were recognized.

8 - tried installing an old Thunderbolt/mini display hot fix from a while back that, upon attempting to install, my computer informed me "you do not need this update"

9 - called Apple support, who ran me through steps 1, 2 and 5 again

10 - made an appointment at my local Genius Bar, where they ran steps 1, 2 and 5 yet again, and then did some sort of in-store diagnostic that confirmed yet again there was a problem with the Thunderbolt ports. The tech that ran the test suggested the solution was a logic board replacement, but didn't necessarily *recommend* it since it is about the cost of 1/3 of a new iMac (which was pretty much on par with my own thinking).

In my System Report, it indicates "No Thunderbolt hardware found"... Luckily, I am able to work around the issue with my devices since they also have USB compatibility. That said, when I brought my iMac home and continued to explore the issue (i.e. under Services, it shows no Thunderbolt drivers loaded), I did discover that the disappearance coincided with an macOS auto-update that occurred during the night before I first noticed the issue.

On July 13, there was a HP Printer Software Update ("Printer and scanner software for macOS Sierra, El Capitan, Yosemite, and Mavericks"). This was the ONLY change to anything in my system configuration between the time the Thunderbolt ports were working properly and when they stopped. I did call Apple Support back to report the coincidence, and was grateful that the tech seemed sincere, added the note to my support case, and mentioned that he would pass it along to development personnel. I don't believe it will be resolved, however, as nearly every search result that I have found for Thunderbolt ports no longer working -- regardless of the model year of the computer -- indicates that the problem is only successfully "solved" via the installation of a new logic board.

You mentioned that you have a MOTU AVB audio interface. Have you confirmed that you have MOTU's Sierra driver updates?

http://motu.com/newsitems/motu-and-os-x-sierra

It may also be worthwhile to try an OS reinstall using the suggestions I made below for barryfromcocoa to see if that helps.

Thanks for the input...

Yes, the AVB stuff is running both the latest drivers and firmware. Of course, that wouldn't affect the fact that my system report shows "Thunderbolt: No hardware was found". As noted, both the AVB device and the Kanex-connected hard drive work fine via Thunderbolt on my MacBook. Granted, I am still running El Capitan there rather than Sierra, but still, it confirms that my devices and the cables are still working and the problem is with the iMac, not the peripherals.

Speaking of macOS installs -- I neglected to mention that I did indeed try a fresh install of Sierra after returning from the Genius Bar... also to no avail. (That was my last-ditch attempt at a solution after discovering that OS update that had coincidentally been applied when the issue first arose.) I also tried testing the port using the iMac as a targeted display... not something I'd used recently, but something that did work on my iMac in the past back when my Thunderbolt ports were still operating as they should.

I started having this problem at the same exact time as you. I started a new job back in July and I thought it was a problem with my drives. I tested them on my new jobs computers and they all work. I also installed an HP update just as you did around the same time. I am still running Yosemite so I don't think it is a system error. I can't believe an HP update could cause some random act of destruction on Thunderbolt hardware? I am heading to a genius bar to see if they can fix the problem but after reading your thread I don't have high hopes.

YES! Did anything work for you or did you find a solution? None of my thunderbolt ports are working and I'm an editor. This has put me in a very stressful situation. APPLE IS KILLING ME with all these **** updates! My ports stopped working a few weeks ago.

I have 4 Thunderbolt drives and ports, none of them work. With them all plugged in it says. " Thunderbolt: No hardware was found." on the system report. I am running iMac (27-inch, Late 2012) Yosemite. Did not install updates, they just stopped working. I did the SMC and the NVRAM several times. Unplugged everuything overnight, did it again, and it it still says no hardware found. The Thunderbolt drives show up on my laptop, but not my imac. So I know it's not the drives, it's the imac ports.

I tried the posted suggestions and they have not worked.

The issue came up this fall about the same time as I had done some OSX updates. I tried going to High Sierra as a solution but that did not work either. Apparently I can get RGB to work, or an Apple authorized dealer was able to connect an RGB display, but I am using an HDMI adapter to display. Bought a new adapter, without any success.

Here are specifics, and while an adapter cable was plugged in to an HDMI monitor.

Thunderbolt Bus:

Vendor Name: Apple Inc.

Device Name: MacBook Air

UID: 0x00010018044D0F30

Route String: 0

Firmware Version: 27.2

Domain UUID: FE3D150F-BC19-EC52-A8A5-F483C3B3157C

Port:

Status: No device connected

Link Status: 0x101

Speed: Up to 20 Gb/s x1

Current Link Width: 0x1

Receptacle: 1

Link Controller Firmware Version: 0.15.0

Mac OSX 10.13.2 (17C88)

MacBook Air (11-inch, Early 2015

1.6 GHz Intel Core i5

8 GB 1600 MHz DDR3

I ran down the list of self-help suggestions here and elsewhere, and then went into an Apple store for a technical diagnostic on my Thunderbolt 1 port. The solution was getting a Belkin Thunderbolt-to-HDMI adapter. at the Apple store

I had just purchased another off-brand adapter from an Apple authorized reseller, but it was not a Belkin. This replaced my older adapter that worked up until I upgraded to the last version of 10.12.x which I believe began support for Apple TV.

After reading the numerous comments in the Apple community about the TB port issue I am speculating that my need for tech support is probably because Apple OSX 10.13 moved to a higher HDMI standard that supports Apple TV but dropped support for older HDMI driver protocols that worked with older Thunderbolt 1 to HDMI cables. Speculation, but it fits the evidence.

I just had the same thing happen. Lacie ssd little big disk attached and a motu 828e

I just dropped the lacie off for repair as the drive light wasn't working. It just occurred to me that unit has to be connected to be lit!

Anyway, tried DMV reset, pram etc. No luck. Late 2013 iMac 27" i7 running Mavericks

This did not resolve my issues. Specifics are posted elsewhere in this hread