All new users, please read: these are NOT blocking errors!

Hello everybody and welcome to the M001 introduction to MongoDB!

The past few weeks we have had numerous new students repeatedly start new threads, asking about the exact same set of errors. So let’s quickly get them out of the way, so we can save a little time for everybody.

Most importantly, try to understand what you’re actually telling your computer to do with the command(s). Don’t just copy them from the class notes, but understand what each command, flag and parameter means. Otherwise, you will simply keep repeating things “because we did them like that before”, instead of actually learning about MongoDB.


WARNING: shell and server versions do not match
This is a warning, not an error. Do not worry. You can do your coursework just fine.


SyntaxError: missing ; before statement
This occurs when you’re trying to run a Linux/Windows/MacOS command inside the Mongo shell. That’s not possible.

This error most often occurs when a student first runs “mongo --nodb” or just “mongo” and then copy/pastes the full “mongo --host etcetcetc” command to connect to their cluster.

You can quit from the shell with , or by entering the “quit()” command. You must then enter the mongo shell connection command from the Windows/Linux/MacOS shell prompt.


An error occurect while loading navigation: connection … closed
You probably left the mongo shell or Compass open for a long while, without doing anything. Your connection experienced a timeout. Simply close Compass or the shell and then restart it.


Error while trying to show server startup warnings: user is not allowed to do action [getLog] on [admin.]
When you’re working through chapter 2, you will make a cluster of your own on Mongo’s cloud service Atlas. You will also create a user account to connect to the database. >90% of the users will get the error message shown above.

This is not a blocking issue and you can continue your coursework as expected.

The user account that you created will be able to work with the database you made. The only thing that MongoDB is telling you, is that the user cannot perform one very specific high-privilege action. This action is not required for M001.

Check here for a full explanation.


Last known master host cannot be reached, or
Connection attempt failed: Network TimeOut, or
Error connecting … socket operation timed out

Yeah… all of these are the same: you had a working connection to the database, but then you stopped working with Compass or the shell for a while. Thus the connection was closed by the server.

Solution: close the client and re-open it with a new connection.


I cannot find database X or collection Y, or
The fields in this database are not the same as shown in the example.

You have most likely mixed up the shared student cluster and your private cluster on Atlas. These two clusters are very different and have very differing contents.

VBoxManage.exe: error: VT-x is disabled in the BIOS …

Your system is currently not set up to allow for efficient virtualization. See here ->

Error while trying to show server startup warnings: user is not allowed to do action [getLog] on [admin.]

This is NOT an error. You have connected just fine, but the user account in question is not allowed to do some checks against the admin database. Don’t worry, things will work just fine.