Message for anyone still searching for temporary solution!
None of the above worked for me. Deleted Appdata folders - DDC - Empty project… I still get the warning. Because it’s annoying and flooding the output log, until someone find a solution, I disabled the LogPackageName log completely with adding those lines in DefaultEngine.ini.
[Core.Log]
LogPackageName=all off
Credits goes to that post:
https://forums.unrealengine.com/t/temporarily-disable-log/363133
Hope that helps someone…