1..3.5.3 keeps crashing

Every now and again my frames will drop form 60 to 10 or less or just freezes and then crashes.

The crash log:
24/07/2018 12:59:36
System.UnauthorizedAccessException: Access to the path is denied.
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.FileStream.WriteCore(Byte[] buffer, Int32 offset, Int32 count)
at System.IO.FileStream.FlushWrite(Boolean calledFromFinalizer)
at System.IO.FileStream.Dispose(Boolean disposing)
at...

1..3.5.3 keeps crashing