Meteor: Unexpected mongo exit code 14. Restarting.Can't start mongo server

If you're having this issue running Ubuntu inside Vagrant/VirtualBox, then the problem come from working in the synced vagrant folder. The workaround is to initialize the .meteor directory in the home directory and to mount it in the synced folder. Assuming your meteor app is called MyApp and the /vagrant is the synced folder, here's how to do it:

cd ~  
meteor create MyApp  
cd MyApp  
meteor  
cd /vagrant/MyApp  
sudo mount --bind ~/MyApp/.meteor/ .meteor  
meteor  

Try:

meteor update --release *LAST STABLE VERSION FOR YOU*
meteor

If it's still not working, try:

meteor reset
meteor

Otherwise, if that still doesn't work, try removing the local db folder then running meteor again like this:

rm -r .meteor/local/db folder
meteor

Also experienced this problem. To fix the problem in my case i needed to remove /tmp/mongodb-<port>.sock file