Dear Community,

During our quality analyses we have identified a possible critical behavior after a firmware update to FW 2021.0.

Under certain circumstances, an invalid project configuration may occur on the controller after a firmware update.
In this case, the controller cannot start the project and further project downloads are rejected.

Typical footprints are as follows:

• The "Fail" gets active directly after the FW update were performed and succeeded.
• It is not possible to deploy a new project via PLCnext Engineer.
• The Output.log (/opt/plcnext/logs/) does show the following exceptions.
  
  ERROR - Exception occurs while loading plc component 'Arp.Plc.Esm': Exception of type 'Arp::System::Commons::InvalidConfigException' was thrown
Task 'Globals' already defined.

or
  
  ERROR - Exception occurs while loading plc component 'Arp.Plc.Esm': Exception of type 'Arp::System::Commons::InvalidConfigException' was thrown
Task 'ServiceTask' already defined.

Remedy:

The cause of the issue is a change in the way some system internal tasks were configured.
Under special circumstances, a duplicate configuration may occur in the overlay file system.
This can happen if, for example, the project folder /opt/plcnext/project has been manually copied to the controller or if a download change operation were declined.

In any case will the following options resolve the fault:

1. Perform a factory reset via PLCnext Engineer (Cockpit)
2. Perform a factory reset type 1 via ssh (Factory Reset)
3. Delete the following files in the /upperdir/
   
   

After restarting, does the control boot at least in ready mode and a new project can be deployed.

We will release in the next weeks the Hotfix 2021.0.2 which will prevent the described problem.

We apologise for the inconvenience.