Question ProBuilder meshes missing after reimport of project

Hey community,
I just shifted my all assets to a new project. I saw that all the meshes that I made in probuilder are disappeared. I then imported the probuilder package from the package manager, still they are not appearing...
The editor gives the following errors:

NullReferenceException: Object reference not set to an instance of an object
UnityEngine.ProBuilder.Normals.CalculateNormals (UnityEngine.ProBuilder.ProBuilderMesh mesh)

UnityEditor.probuilder.probuildermeshpreview was not disposed properly. make sure that base.cleanup is called if overriding the cleanup method.

How can I solve this issue? I want my probuilder meshes...

 

Also, the probuilder meshfilter component shows that lightmap uvs are missing, but when I click the "Generate Lightmap UVs button, nothing happens.

 

I have the same problem

 

I have a similar problem

I created a new project and move all of my old project on the new one all of my objects and walls (House) made by probuilder were there despite probuilder was not installed but after when i install probuilder version 4.5.2
everything has disappeared..

i try repair and fix noting work and i even removed probuilder and retry on new update or lower and nop..
so i put my object and wall on a other project with probuilder and nothing showing..


if you managed to do what please tell me !

 

None dude,
I had to make a new one...

 

Having the same issue.

Also similar to what's happening here, from as far back as 2019: https://forum.unity.com/threads/problem-with-disappearing-probuilder-meshes.758441/, I believe.