"All compiler errors have to be fixed before you can enter playmode". How do I fix this?

Questions & Answers
1

This is what it says when I open up the console:

Internal compiler error. See the console log for more information. output was:
Unhandled Exception: System.UnauthorizedAccessException: Access to the path “C:\Users\Austin\Documents\SurvivalGame\Temp\Assembly-CSharp-firstpass.dll.mdb” is denied.

at System.IO.FileStream…ctor (System.String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, Boolean anonymous, FileOptions options) [0x00000] in :0

at System.IO.FileStream…ctor (System.String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, Boolean isAsync, Boolean anonymous) [0x00000] in :0

at System.IO.FileStream…ctor (System.String path, FileMode mode, FileAccess access) [0x00000] in :0

at Mono.CompilerServices.SymbolWriter.MonoSymbolWriter.WriteSymbolFile (Guid guid) [0x00000] in :0

at Mono.CSharp.SymbolWriter+SymbolWriterImpl.WriteSymbolFile () [0x00000] in :0

at Mono.CSharp.SymbolWriter.WriteSymbolFile () [0x00000] in :0

at Mono.CSharp.CodeGen.Save (System.String name, Boolean saveDebugInfo, Mono.CSharp.Report Report) [0x00000] in :0

at Mono.CSharp.Driver.Compile () [0x00000] in :0

at Mono.CSharp.Driver.Main (System.String args) [0x00000] in :0

2

Close Unity, turn off McAfee temporarily, retry. Many posts on the top err …CSharp-firstpass.dll.mdb is denied… seem to point to Virus scanner as culprit.

Edit: changed to Answer