P: Canon tethering stopped working after updating to Lightroom Classic v15.4

this same thing is happening to me and I have a shoot tomorrow...what a nightmare.

Whatever you updated doesn't work with my R6m3, you’re costing me a lot of time, money and patience...

Thank you Adobe for causing a catastrophic mess during a shoot when you decided to automatically update Lightroom Classic with “improved tethering.” You cost me money and time and you should really better test these improved features before forcing updates on people.

The tethering functionality for Canon was rewritten in 15.4, there seem to be some issues. You can disable it in preferences to go back to the old version. More info here: 

I’m stuck on LRC 13.5.1 due to tethering issues with the Fuji GFX100. After that Adobe added native support for the GFX100, but it’s missing tons of camera settings that are necessary for controlling camera settings while doing tethered shooting. I brought this up in this forum and answered some questions for the adobe experts that were engaging, but ultimately I had to downgrade LRC and leave it there. 

Just lost a prospective client due to the tethering problem. Not only couldn't get the images to write on the computer, but due to the buffering I couldn't write them down properly on my cards. It was showing me "card full" message after shooting just few images. I kept swapping cards and still had the same problem. I was suspecting camera failure (I have R5 mark II). 

Lots of stress, very unhappy client and wasted studio session. I don't understand how this is even called a professional software for photographers. Absolutely livid - lost time, money and got a serious reputation hit.

Paying almost £70 monthly for this.

After swapping cables, computers, cards finally realised it is the Lightroom. Changing the option to Canon SDK in Preferences finally fixed it for me, but way past the session time. 

Adobe, work on the basic functionality and optimisation rather than AI junk. Seriously, this is just ridiculous.

Hi Adobe community, 

Recently my R5 MrkII has not been able to send a photo to LrC while tethered. I am able to control the camera’s settings and trigger the release through LrC, but it wont save the photo. The photo count flashes as though it's trying to save the image. It successfully saves the image locally on the SD but fails to send it to the computer. This issue started seemingly out of no where; Canon forums think it may be linked to the MAC 26.5.1 update, though Im not entirly sure when the update happened on my computer. I think this counts a bug for your review. 

Troubleshooting so far:

Restarted everything, R5 Firmware updated, checked for computer and LrC updates, tried alt cables (original cables and tethering work on an R6 MkII), disabled all communication settings, reset communication settings, restarting the tether handshake, and resetting Lightroom Classic preferences.

Hardware - Firmware - Software 

Camera: firmware was 1.1.1. when issue presented itself, updated to 1.3.1 as part of troubleshooting. 

Tether cables: Canon C-to-C cable that came with the body to a Tether Tools C-to-C extension cable.

Computer: MacBook M3 Pro - macOS Tahoe 26.5.1 - current version as of time of post. 

LrC: 15.4.1 - current version as of time of post. 

Seems like Adobe’s new “Improved tethering for Canon Cameras” needed a lot more thorough testing by Adobe before releasing it?

I also found that checking “Use Canon SDK for tethering Canon cameras” solves the problem. So the native Adobe tethering doesn’t seem to work properly?

Yes.  I get a “Full” message after shooting 13 frames on my Canon EOS 5DS with Lightroom 15.4.1 tethered. I can fix it temporarily by shooting one frame from the tethered control bar on the screen, but the problem recurs after shooting 13 more frames on the camera. Happens EVERY time after exactly 13 frames. Neither the camera card nor my computer hard drive are anywhere near full.

This version was billed as “Improved tethering for Canon Cameras” ???