Unity won't start; Moving file failed

Unity Engine
1

I am getting an error since I upgraded unity from 3.3 to 3.4 today.
When I try to start unity I get a message which says:
Moving file failed

Moving Temp/Assembly-UnityScript.dll.mdb to Library/ScriptAssemblies/Assembly-UnityScript.dll.mdb failed: The system cannot find the file specified.

can anyone help me with this?
Thanks in advance

2

I get a few errors when starting unity that look just like this, except mine say access denied. If I hit “Try Again” a couple of times, though, it works.

Mine only happen when creating a new project.

Not sure of the cause. So far I have had very few problems at all with Unity.