Error code 1012 when trying to deploy to the trial cloud

When I try to start my first trial instance (Pizza Mario) from the Modeler, I get the following error message: An error occurred (error code 1012). Please contact Mendix for more information. Cleaning does not help, the error stays, and therefore the instance stays on status Stopped.
8 answers

I did further investigations and found out a way to get it working. So I can successfully get it deployed when following these steps:

  1. Open the Modeler
  2. Open recent project Mario Pizza
  3. Press Run => Fails with error 1012
  4. Press button Clean (under My Instances) and select Project->Clean Deployment Directory
  5. Press Run => Fails with error 1012
  6. Open recent project MyFirstApp (this causes project Mario Pizza to close, and opens MyFirstApp project)
  7. Press Run => Fails also with error 1012
  8. Pres button Clean (under My Instances) and select Project->Clean Deployment Directory
  9. Press Run => Success !!! (I can access the app via the browser)
  10. Open recent project Mario Pizza
  11. Press Run => Success !!!

To come back in the error 1012 situation: 12. Press button Clean (under My Instances) 13. Run => Fails with error 1012

To Solve Repeat step 6, 8, 9, 10 and 11.

Some information: I am using Mendix Business Modeler Version 2.5.1 Trial (build 167) JDK 6 Update 21 Microsoft .NET Framework 3.5 SP1 Microsoft Windows [versie 6.0.6002] (Vista)


This problem occurs when a module in a project has been renamed in combination with having an autonumber attribute in the domain model of this module. The issue is currently being resolved, next week we expect to release an update in which this problem will not occur anymore.

Meanwhile a workaround for this problem is:

  1. Use the "Clean" commando on your cloud dashboard (View -> Cloud Dashboard) in the Mendix Business Modeler. This will empty the project database on the cloud server and will create a fresh one upon the next deployment.

  2. Start a new project or download a project from the App Store (for example ‘My First App’).

  3. Deploy and run your project.

  4. Please be sure to NOT rename a module with having an autonumber attribute in the domain model. All other changes can be done without problems.

We apologize for the inconvenience and hope further deployments will run smoothly for you.


Which version are you using exactly? This error code usually signals a version mismatch. You can find the build number under Help | About Mendix Business Modeler.


Same thing happens to me too. Any other way to try?


I did all the above, but no success. The error 1012 is there to stay. I think it is very poor that the most simple sample app has this bug (and for several months) every newby has had it, and is not been fixed until the 2.5.3 version, which can only be downloaded with a new subscription. Not really motivating to investigate the platform . . .


I'm using 2.5.4 but keep getting the same error, even with an empty project...


Can you try to clean your slot and try again?


Start, Stop and Clean are all greyed out in My Instances. Is this normal?