KB-1574 Process model swim lanes disappear and connectors become diagonal

Symptoms

Swim lanes disappear in a process model, and horizontal connectors display as diagonal connectors upon opening the process model. This change is depicted in the screenshots below:

In addition, the application server log prints one of the following error messages:

1. "Access is denied" error:
   
   

   ERROR com.appiancorp.process.design.service.ProcessDesignServiceXmlImpl - An error occurred retrieving the model from the filesystem.
   java.io.FileNotFoundException: <APPIAN_HOME>\_admin\models\<XXX>\<PM_UUID>\draft.xml (Access is denied)

   
   
   
2. "The system cannot find the path specified" error:
   
   

   ERROR com.appiancorp.process.design.service.ProcessDesignServiceXmlImpl - An error occurred retrieving the model from the filesystem.
   java.io.FileNotFoundException: <APPIAN_HOME>\_admin\models/<XXX>\<PM_UUID>\draft.xml (The system cannot find the path specified)

   
   
   
3. "No such file or directory" error:
   
   

   ERROR com.appiancorp.process.design.service.ProcessDesignServiceXmlImpl - An error occurred retrieving the model from the filesystem.
   java.io.FileNotFoundException: <APPIAN_HOME>_admin\models/<XXX>\<PM_UUID>\X.0.xml (No such file or directory)

Note: if you are using Appian 7.11 or earlier and experience the issue depicted in the above screenshots, and the application server log prints a different error message, please reference KB-1001.

Cause

1. The process model's most recent XML file, draft.xml, is not accessible in the filesystem (it is locked, the shared folder is unavailable, or the application server does not have the correct permissions to access it).
2. The process model's most recent XML file, draft.xml, has been deleted from the filesystem.
3. The process model version you are trying to access has a corresponding XML file that is either locked, deleted, or the application server does not have the correct permissions to access it. Removing process model XML files from the filesystem of your site with the Process Model Utilities plugin can cause this behavior for specific versions of your process model.

Action

1. Ensure that the draft.xml file is unlocked and that the appropriate folders in the <APPIAN_HOME>\_admin\models shared directory are accessible. In addition, ensure that the user that is running Appian has appropriate permissions on the draft.xml file. To prevent this issue in the future, do not virus-scan or back-up the models folders during business hours.
2. Restore the XML file from a back-up. To prevent this issue in the future, do not delete XML for models directly from the filesystem.
3. If using the Process Model Utilities plugin, adjust PM Cleanup Settings in order to preserve XML files associated with process model versions that will still need to be accessed.

Affected Versions

This article applies to Appian 16.1 and later.

Last Reviewed: October 2019