Market Place Blocker App - OS showing optional royalties

Hi all

I have a contract that I launched last summer 2022, and also one I launched on Jan 1st 2023.

Since hearing about the new OS stance on royalties, I have tried to enable Market Place blocker on the first contract and it displays a message saying:

‘Contract Version Error
You cannot install marketplace blockers on contracts deployed with Manifold before December 1st, 2022.’ - Is there any workaround on this or are we stuck?

However, my second contract was deployed Jan 1st 2023. I have tried to enable to Market Place Blocker and each time it say :

’ Something went wrong
Extension already registered, please contact Manifold team at

So, here I am. As on OS at the moment the royalties for the editions on that contract are showing as optional when trying to sell on OS. Yet in the Manifold dashboard it saying the extension already exists. So not sure what’s happening.

Contract name: 8-Bit Sport - Culture Club

Would be great if someone could help me with this please. Also, clarification if the Market Place Blocker will work with the new OS stance on royalties.


I have the same issue…same error “Extension already registered…”

I would like to block Opensea as well as all sudo, blur, looksrare

would also love a solution for this. manifold?

Hi Manifold team

Just bumping this. I appreciate this is perhaps not seen as high priority, but it has been 3 weeks since the original post.

Would be great if anyone can help with this :raised_hands:t3:


Opensea has moved to all royalties being optional unfortunately.

If the extension is already registered (I’m assuming you’re talking about the marketplace blocker app), you should be able to select and block marketplaces. However, be aware that this is likely unsustainable as they keep releasing new contract versions.

yes…in my case, it is already registered, but i am getting the same error mentioned above when I try to add these marketplaces to the blockers on my contracts

Interesting. Can you share a screenshot please which shows this? Will help us debug.

Ok, the reason you get that error is because you CANNOT have BOTH the operator filterer (OpenSea) AND the marketplace blocker installed at the same time.

Please disable one before using the other, and vice versa.

Okay - thank you, I will try this! :100:

If you want to remove the marketplace blocker as well, here is how to do it:

Hi Wilkins - did you see my original post refers to a contract deployed after Jan 1st 2023 and I posted a screenshot showing the error which advised me to contact Manifold? Can you check the full details of my original post again please and let me know what you think. Thanks!

Yes. So if contracts are deployed prior to December 1, 2022, there is no support for marketplace blockers.

If you encounter the other errors, it means you can only have the OpenSea Operator Filterer OR the marketplace blocker installed. You cannot have both. You just remove/disable one before enabling the other.

Further, with OpenSea’s latest change to optional royalties, and the fact that new contract are continuously deployed, marketplace blockers aren’t really effective anyways.

Appreciate the help, thanks.

Do you know if there is any benefit to either Operator Filter or Marketplace blocker? I terms of which is ‘better’, for want of a better term.