But why does it change? I used corona since 2 years on mac and till version 10 was all fine. But since Version 11 it doesn’t work anymore.
The OIDN denoiser was updated, so a new version is being used compared to the previous version. This new version includes, as an example, the ability to use GPU (but there are some other changes to it too that improve it on CPU). So, it is not the same Intel OIDN denoiser as used in 10.
We've updated to this new version in Corona 11, but as Marcin notes, currently this only works on Windows in our current implementation. Which means Corona 11 on macOS can't use the updated OIDN denoiser at the moment, until we update our implementation.