'Failed to unlink socket file" error in MongoDB 3.0

This issue occurs when you use the command

mongod

Before using the command

sudo service mongod start

To fix the issue, either:

Set appropriate permissions on the file:

/tmp/mongodb-27017.sock

OR

Remove the file

/tmp/mongodb-27017.sock

Run

sudo service mongod start && mongod

Alternative to the answer provided by KurioZ7, you can simply set the permissions of the .sock file to the current user:

sudo chown `whoami` /tmp/mongodb-27017.sock

This does the trick for me if I want to run mongod without sudo. If I delete the file like in KurioZ7s answer, I will simply get the same error the next time I restart my machine.

I have fixed this issue myself, by deleting the mongodb-27017.sock file . I ran the service after deleting this file, which worked fine. However, I am still not sure the root cause of the issue. The output of the command ls - lat /tmp/mongodb-27017.sock is now

srwx------ 1 mongodb nogroup 0 Apr 23 06:24 /tmp/mongodb-27017.sock