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When compiling a WorkPlace Tech application created with an earlier version of WPT and Visio, an "Unhandled Write Error" or other Visio error occurs.


When compiling a WorkPlace Tech application created and successfully compiled with an earlier version of WPT and Visio, an error message may be displayed indicating an issue with an object in the application.  One of the observed errors is noted below:

"Unhandled write error (app name) (object name)"


WPT 5.6.x

WPT 5.7.x

WPT 5.8.x


Internal consistency error in the internal application database.

This issue will sometimes occur when the application was created in one version of Visio then updated to a newer version.  The actual causes are not fully understood.  Because the history of the actual application file is frequently unknown, having been created and modified by various engineers, these issues usually cannot be duplicated.

Prior to WorkPlace Tech Tool version 5.x.x the application database was stored in the WPT project database. 
In WPT version 5.x.x, the application database is stored internal to the WPT application drawing Visio file.


  1. Open the application file in the WorkPlace Tech Tool and allow it to be saved in the newer Visio file format, if prompted.
  2. From the "Application" menu of WPT, select "Rebuild Application"
  3. Click the [Yes] button to allow the application to be rebuilt. 
  4. A popup window will display the process of the application rebuild. If errors are detected, appropriate steps must be taken to correct them.
  5. If you are rebuilding an MNL-800 application and have not previously manually indexed all the Echelon network variables (SNVTs), the SNVT index numbers may change.  This change of SNVT index numbers can cause issues with existing network bindings to or from the controller.  If some or all SNVTs were not indexed, and they changed as a result of the rebuild, you will need to follow the list of sub-steps listed here.
    1. Using the WPT Hardware wizard, change the "Controller Program ID" then compile and download the application to the controller
    2. If the network is managed using LonMaker, perform a "Replace" on the controller object, reading the XIF file from the device.
    3. If the network is managed by an I/A Series R2 UNC and WorkPlace Pro, you will need to delete the existing device shadow object and re-learn the controller then recommission the device and recommission the Local Lon Device..
    4. Update any binding links that were changed or moved due to the replacement of the controller shadow object.
  6. Compile and download the application.
  7. Rebind all links to the updated controller
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Last update:
‎2018-09-06 01:12 PM
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