I was recently writing a small practice application for learning pursposes. The task was to read windows log file: %windir%/WindowsUpdate.log and find "exit code" numbers. The problem I encountered was to actually open properly file. I was receiving exception: System.IO.Exception with message: "Additional information: The process cannot access the file 'C:\WINDOWS\WindowsUpdate.log' because it is being used by another process." my code looked something like that: string windir = System.Environment.GetEnvir... ......