maps out of sync / is in timestamps but is not known in guidmapper

Unity Engine
1

I get these errors fairly often out of no where. I know deleting the Library folder or reimporting all assets fixes it but is there a way to prevent this from happening?

Timestamps (1775) and assets (1780) maps out of sync.
Asset '' is in assets but has no assettimestamp...
Asset 'C:/Program Files/Unity 5.1.3f1/Editor/Data/UnityExtensions/Unity/GUISystem/UnityEngine.UI.dll' is in timestamps but is not known in guidmapper...
Asset 'C:/Program Files/Unity 5.1.3f1/Editor/Data/UnityExtensions/Unity/Networking/UnityEngine.Networking.dll' is in timestamps but is not known in guidmapper...
Asset 'C:/Program Files/Unity 5.1.3f1/Editor/Data/UnityExtensions/Unity/Networking/Editor/UnityEditor.Networking.dll' is in timestamps but is not known in guidmapper...
Asset 'C:/Program Files/Unity 5.1.3f1/Editor/Data/UnityExtensions/Unity/GUISystem/Editor/UnityEditor.UI.dll' is in timestamps but is not known in guidmapper...
2

Anyone know about this? I am seeing this a lot.

3

Its a known issue, what version are you using?

4

5.1 and 5.2 but I think it mostly happens in 5.2 as far as I can remember.

5

If its in 5.2 then could you file a bug report? Unity QA: Building quality with passion