IIS Server message on starting a website - "The process cannot access the file because it is being used by another process"

ERROR MESSAGE: "The process cannot access the file because it is being used by another process"


EVENT LOG ENTRY: "Unable to bind to the underlying transport for 0.0.0.0:80. The IP Listen-Only list may contain a reference to an interface which may not exist on this machine.  The data field contains the error number."


PROBLEM: I ran into this issue where I was trying to connect to my Virtual Server Administration Website and all I would get is the "Page not found" error. I opened the IIS MMC snap in and it showed my Default Website as Stopped. On trying to start the website, I would get the following error: "The process cannot access the file because it is being used by another process".


I have the following system configuration:

• Windows XP x64 as the Host Operating System
• IIS 6.0 running on the Host Operating System
• Microsoft Virtual Server 2005 R2 SP1
• Windows 2003 32-bit as the Guest Operating System
• Skype running on my Host Operating System

SOLUTION: Here is a Microsoft KB article that describes why the problem is occurring and suggests some fixes. However, even before I tempered with the registry, I was curious to find out what running application may be using the port 80. As I checked the list of my running processes from the Task Monitor, I saw skype. I went in the advanced settings of Skype (Tools -> Options -> Skype) and realized that I had checked the option to allow Skype to listed on port 80 & 443. I shut down skype, restarted the http service and IIS service and the problem was gone.