title: What does (EC2) 'AMI: Unavailable' mean and how should I handle it?
body: <p>I'm running two EC2 instances, (Linux and Windows) on AWS, which initiated based on AMIs provided by Amazon. Everything works fine, but since a couple of weeks, I noticed that on Windows Instance, under "Description" tab, it says that "AMI: Unavailable (ami-f0c9ff84)". </p>
  
  <p>I have not performed a reboot on that EC2 for more than a month and I'm curious if everything will work again seamless after reboot. Is "AMI unavailable" a serious problem? Why the AMI is not available any more? I'm not sure if I need to take some actions from my side (e.g. to get an EBS snapshot in case of failed reboot, whatever). </p>
  
  <p>Should I be afraid that restarting the instance will not work while it says "AMI unavailable"? </p>
  
  <p>Thanks in advance!</p>