I have attached Volume to instance ready, But Still get error

This error comes when Device name given while attaching the root volume differs from Root device attached to EC2 instance during launch.

In the above screen shot error is related to device name /dev/sda1. We need to use same device name while attaching the volume to EC2 instance.

• Go to EBS –> Volumes and select respective attached volume . This volume will be having status as “in-use”. Then click on Detach volume option from Action drop down menu.
• Try to attached same volume to EC2 instance. However make sure that you are not using default “Device” such as “/dev/sdf” Instead Use Device name as /dev/sda1 and click Attach Button.
• This time when you try to start the instance, the error “Instance does not have a volume attached at root (/dev/sda1)” will not occur and your EC2 instance will be start successfully.