Cannot delete network interface associated with now-deleted EC2 instance, blocking removal of other items (VPC, SGs)

Question

I deleted an EC2 instance, which left behind a bunch of cruft.  I cannot remove one Network Interface because it is claimed to be "in use".  The interface's description (somewhat anonymized) is below:
[Updated from a comment below: The VPC state shows as "available", and I have no File Systems or Access Points in Amazon EFS.

"Description": "EFS mount target for fs-** (fsmt-**)",
            "Groups": [
                {
                    "GroupName": "efs-sg-1",
                    "GroupId": "sg-**2"
                },
                {
                    "GroupName": "default",
                    "GroupId": "sg-**9"
                }
            ],
"IntefaceType": "efs",

Steve_M · Accepted Answer

Going through the output of `aws ec2 describe-network-interfaces --network-interface-ids eni-1234567890abcdefg` should provide details of everything the interface is associated with, and if there is something lurking inside your config that you haven;t noticed yet then this should bring it to prominence.

It's slightly curious that you have a security group called efs-sg-1 but don't have any EFS filesystems. Is this SG associated with anything else, or just the interface in question here?

iBehr · Answer

Based on multiple mentions in the description, I believe that is an interface in your VPC for an Elastic File System (EFS) endpoint and was not an EC2 instance interface.  Please check the "Status" column and you will likely find it listed as "In Use".

Cannot delete network interface associated with now-deleted EC2 instance, blocking removal of other items (VPC, SGs)

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