Bug Failed to unload 'ProjectSettings/UnityAdsSettings.asset' (826788)

load up a 5.4 project and be greeted by sprite instances that have lost their material - now that's what i call alpha!

 

Load up a 5.5 project and have the same error: Failed to unload 'ProjectSettings/UnityAdsSettings.asset'

 

After update, load a 5.4.1f1 project under 5.5.0f3 :

2 warning
Platform MacStandaloneSupport does not support graphics device type OpenGL
Platform LinuxStandaloneSupport has only one supported graphics device type (OpenGL Core)

And the same error
Failed to unload 'ProjectSettings/UnityAdsSettings.asset'

 

Same error on 5.5.0f3.
In the console log is says:
Refresh: elapses 0.330112 seconds
Refresh: trashing asset 00000000000000008100000000000000
Failed to unload 'ProjectSettings/UnityAdsSettings.asset'
Then Unity Crashes when I run it.

 

!!!!This is happening on any project I try to load from a saved version of any previous Unity Project.!!!!
This is a major issue.

 

I finally got it to run by disabling the Unity Ads script.
Very strange.