DRAFT KB-XXXX Process model swim lanes disappear and connectors become diagonal

Symptoms

A process model that used to have swim lanes and/or straight connectors now has no swim lanes and diagonal connectors. This is depicted in the screenshots below:

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

Error 1:

ERROR com.appiancorp.process.design.service.ProcessDesignServiceXmlImpl - An error occurred retrieving the model from the filesystem.

java.io.FileNotFoundException: <APPIAN_HOME>\_admin\models\<PM NUUMBER>\<PMUUID>\draft.xml (Access is denied)


Error 2:

ERROR com.appiancorp.process.design.service.ProcessDesignServiceXmlImpl - An error occurred retrieving the model from the filesystem.

java.io.FileNotFoundException: <APPIAN_HOME>\_admin\models\<PM NUUMBER>\<PMUUID>\draft.xml (The system cannot find the path specified)


Error 3:

<Insert error here>

Cause

1. Error 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. Error 2: The process model's most recent XML file, draft.xml, has been deleted from the filesystem.
3. Error 3: There is a mismatch between the process design and the filesystem. This can happen when the environment engine database KDB file for design (pd*.kdb) has been reverted to a previous date. In this case, the older KDB file will not include the most recent transactions performed on the process model. This will cause a mismatch between the pd*.kdb file and the draft.xml file.