topic Re: EOS R6 Mark II: Error 01 in EOS DSLR & Mirrorless Cameras

EOS R6 Mark II: Error 01

Gaby1 — Sun, 24 Aug 2025 12:31:34 GMT

I am using the Canon EF-EOS R Mount Adapter for my Sigma 150 - 600 mm lens. The AF menu defaults to MF which it doesn’t allow me to change. I suspect it’s a connection/contacts issue but it’s a brand new camera and a brand new adapter.

Re: EOS R6 Mark ii: Error 01

deebatman316 — Fri, 22 Aug 2025 01:23:51 GMT

Have you tried a Canon brand lens to see it will work or not. The EOS R6 Mark II & EOS R7 are finicky with 3rd Party lenses.

Re: EOS R6 Mark ii: Error 01

Gaby1 — Fri, 22 Aug 2025 01:33:44 GMT

No, I haven’t, but sounds like I might have to spend the money. Thanks for your fast response.

Re: EOS R6 Mark ii: Error 01

deebatman316 — Fri, 22 Aug 2025 01:39:38 GMT

What I’m suggesting is to test the mount adapter out. To see if the mount adapter or the lens is at fault. It can be any Canon brand EF lens. I would also test a native RF Mount lens to see if it will communicate with the camera.

Re: EOS R6 Mark ii: Error 01

March411 — Fri, 22 Aug 2025 02:31:16 GMT

I had issues with my Sigma 60-600mm and it ended up needing a firmware update. I had to pick up a dock but it was worth it, resolved all my issues. If you are located in the states I can send it your way if you don't have one. If you are interested shoot me a DM.

Re: EOS R6 Mark ii: Error 01

Gaby1 — Fri, 29 Aug 2025 19:41:24 GMT

Yes, I tried it with a Canon 70-300 mm lens, also with my brand new EF to EOS R Mount adapter; didn’t solve the issue.

Re: EOS R6 Mark ii: Error 01

Gaby1 — Fri, 29 Aug 2025 19:45:36 GMT

Thanks Marc. I just received the dock I bought for upgrading the Sigma firmware. Will try it tomorrow. I am skeptical though since I experience the same autofocus/communication issues with a native Canon lens I just purchased. It’s an EF lens, so I am still using the mount adapter.

Re: EOS R6 Mark ii: Error 01

deebatman316 — Fri, 29 Aug 2025 20:45:04 GMT

Which Canon 70-300mm lens. Canon has released 3 of those lenses one of which is an L model. This one is the easiest to identify out of the other two. The L model is painted white instead of black. The newer version II says “Nano USM” and has an LCD screen on it. The original lacks a focus distance window on it because it uses a cheaper Micro USM AF motor. It also doesn’t provide Full Time manual focus like the other 2 lenses. I have pictures below to help you identify your lens model.

Re: EOS R6 Mark II: Error 01

March411 — Fri, 29 Aug 2025 20:45:21 GMT

Good luck Gaby although I would tend to agree with you if it is happening with other Canon EF mount lenses.

I would go back to deebatman316 suggestion especially if you have a local retailer in your area that has an EF/R adapter and RF lenses. If it's the adapter and under warranty it should be easy to resolve.

"What I’m suggesting is to test the mount adapter out. To see if the mount adapter or the lens is at fault. It can be any Canon brand EF lens. I would also test a native RF Mount lens to see if it will communicate with the camera."

Re: EOS R6 Mark ii: Error 01

Gaby1 — Sat, 30 Aug 2025 00:18:04 GMT

I bought the 70-300 mm lens used, it’s not the L model, but the EF 1:4-5.6 IS II USM Lens. It’s the one from your last picture.

Re: EOS R6 Mark II: Error 01

Gaby1 — Sat, 30 Aug 2025 00:19:39 GMT

I think I will go to a local retailer; thanks for the suggestion.

Re: EOS R6 Mark ii: Error 01

FloridaDrafter — Sat, 30 Aug 2025 02:36:16 GMT

@Gaby1 wrote:

Yes, I tried it with a Canon 70-300 mm lens, also with my brand new EF to EOS R Mount adapter; didn’t solve the issue.

Hello, Gaby!

Sorry I'm late to the thread and I realize you probably have went to your local dealer by now. But my wife uses the R6 II and for a while, she used the EF 70-300 f/4-5.6 IS USM II Lens, so I know it works. She used the plain Canon brand adapter. So there may be other issues at play.

Newton

Re: EOS R6 Mark II: Error 01

Gaby1 — Sat, 30 Aug 2025 03:05:06 GMT

Thanks for that comment. Yes, maybe it’s something with the camera.

Re: EOS R6 Mark II: Error 01

March411 — Sat, 30 Aug 2025 03:17:55 GMT

You'll have a pretty good idea once you visit your local retailer and test a different EF/RF adapter and have a chance to mount a RF lens.

When did you purchase the body and did you get a CarePak?

Re: EOS R6 Mark II: Error 01

Gaby1 — Sat, 30 Aug 2025 03:45:52 GMT

I purchased it a few weeks ago on eBay used, but “in mint condition”. I haven’t gotten the Care Package yet, I will see if I can still do that.

Thanks again for all your help.

Re: EOS R6 Mark II: Error 01

K_ozdragon — Sat, 30 Aug 2025 06:20:07 GMT

Do your lenses have a AF to MF switch? If so, & it's turned to MF, the option will be greyed out in the camera menu. Make sure your camera firmware & lens firmware are all updated, along with the adapter. Using old firmware on any of the equipment can cause issues. Particularly with compatibility.

Another thing to check is the focus mode you're using. AI detection will turn off the focus option. Also, if the camera has custom settings mapped, it may turn off the menu option in the camera. This could be highly likely since your camera is used. Consider doing a factory reset on the camera to ensure there's no odd settings or remapped buttons. Or check the custom configuration settings to see if the AF to MF setting has been remapped. Honestly, a full reset would be best to get everything to default. Then make sure your firmware is all up to date.

Re: EOS R6 Mark II: Error 01

Gaby1 — Sun, 31 Aug 2025 17:42:11 GMT

Thank you for your suggestions- in the meantime I resolved the issue by taking my R6 to a retail store and trying out different lenses and another mount adapter: it was the brandnew Canon mount adapter I had purchased at Amazon that caused the issue.

Re: EOS R6 Mark II: Error 01

K_ozdragon — Sun, 31 Aug 2025 23:15:19 GMT

Ah, that will definitely do it. It could have been firmware on the adapter, but more than likely it was a fake adapter. Amazon is unfortunately filled with counterfeit goods. It's a really big issue. They make it look like an official OEM product, but it's just a cheap $15 knock off under the hood.

Of course, it could just be a faulty adapter, but when dealing with Amazon, it can often be a counterfeit good. Either way, glad you sorted it out & got it working. Hopefully you can get a return on the Amazon adapter to get your money back. Going to a store & checking your equipment when it comes to things like adapters is a great way to quickly narrow down an issue. I'm sure you felt relieved when it began working lol.

Re: EOS R6 Mark II: Error 01

deebatman316 — Sun, 31 Aug 2025 23:21:42 GMT

The Canon brand adapter doesn't have firmware. All it serves is as an extension tube with electronic contacts for EF lenses that puts it at the correct distance from the image sensor. The adapter isn't converting camera body signals from RF-EF. The camera detects which lens is mounted and appropriately switches to EF Mount communication when an EF lens is used. Another rule stayaway from any online marketplaces like Amazon, Walmart and Facebook. Stick with well know and authorized dealers.

Re: EOS R6 Mark II: Error 01

March411 — Mon, 01 Sep 2025 01:35:48 GMT

I would agree with Demetrius that it is best to stay away from unauthorized dealers. I attached the current listing below (PDF) of Canon authorized sellers to this post but please note the last update was 8.15.25.

That being said since you recently purchased this from Amazon you should still be eligible to make a return for defective product. Additionally, if push comes to shove Amazon does have authorized Canon sellers on their marketplace but I would always check the seller prior to making the purchase.