Objects.yaml issues after upgrade v3.2 -> v3.3

Currently i’m upgrading a Neos installation which was still on 3.1.
The upgrade from 3.1 to 3.2 went without issues.

However 3.3 i’m getting a really annoying issue which i can’t seem to backtrace to the root of the problem.

The upgrade itself went fine. Composer, code/doctrine migrations etc.

But now when i open the frontend/backend whatever it fails right away with the Error:

`Cannot set instance of class “Composer\Autoload\ClassLoader” because no matching object configuration was found.

Classes which exist but are not registered are considered to be of scope prototype. However, setInstance() only accepts “session” and “singleton” instances. Check your object configuration and class name spellings

When i go see “Neos.Flow/Configuration/Objects.yaml” the Object is defined right there:

scope: singleton
autowiring: off

I’ve been trying to clear stuff, removing composer packages, packagestates.php, cache, google-ing.
But no luck so far.

Does anyone maybe have a clue in where to look/what to do?

Thanks in advance :slight_smile:

Hey Lars , did you try to clear all caches / remove Data/Temporary?

Yep, got a bit annoyed and created a new dir, copied my packages and config. Started environment et voila… :S
I still don’t know what the issue was however.
Didn’t have the issue on Linux btw.

Strange, obviously hard to say. But sounds a bit like a read error in the file or something like that.