# Can't load installation with variable set in its DataModel

**URL:** <https://forum.universal-robots.com/t/cant-load-installation-with-variable-set-in-its-datamodel/24541>\
**Category:** URCaps SDK\
**Created:** [October 20, 2022, 5:28pm UTC](https://forum.universal-robots.com/t/cant-load-installation-with-variable-set-in-its-datamodel/24541 "2022-10-20T17:28:45Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![anon36982274](https://avatars.discourse-cdn.com/v4/letter/a/e8c25b/32.png) [@anon36982274](https://forum.universal-robots.com/u/anon36982274)\
**Post date:** [October 20, 2022, 5:28pm UTC](https://forum.universal-robots.com/t/cant-load-installation-with-variable-set-in-its-datamodel/24541/1 "2022-10-20T17:28:45Z")

</div>

Getting this when loading installation file with variable set in its DataModel:

```auto
16:43:07.281 ERROR - Fatal error on installation load {thread: AWT-EventQueue-1 , loggerClass: com.ur.view.polyscope.persistence.installation.RobotInstallationPersistence$SerializePersistenceStrategy}
com.thoughtworks.xstream.converters.ConversionException: interface com.ur.view.variables.core.Variable: Cannot find class com.ur.view.variables.core.Variable : Cannot find class com.ur.view.variables.core.Variable
---- Debugging information ----
message : Cannot find class com.ur.view.variables.core.Variable
cause-exception : com.thoughtworks.xstream.converters.reflection.ObjectAccessException
cause-message : Cannot find class com.ur.view.variables.core.Variable
class : com.ur.view.variables.core.Variable
required-type : com.ur.view.variables.core.Variable
path : /Installation/Contributions/URCaps/Contributed[3]/Variable/variable
line number : 247
------------------------------- : interface com.ur.view.variables.core.Variable: Cannot find class com.ur.view.variables.core.Variable : Cannot find class com.ur.view.variables.core.Variable
---- Debugging information ----
message : Cannot find class com.ur.view.variables.core.Variable
cause-exception : com.thoughtworks.xstream.converters.reflection.ObjectAccessException
cause-message : Cannot find class com.ur.view.variables.core.Variable
class : com.ur.view.variables.core.Variable
required-type : com.ur.view.variables.core.Variable
path : /Installation/Contributions/URCaps/Contributed[3]/Variable/variable
line number : 247
-------------------------------
message : interface com.ur.view.variables.core.Variable: Cannot find class com.ur.view.variables.core.Variable : Cannot find class com.ur.view.variables.core.Variable
---- Debugging information ----
message : Cannot find class com.ur.view.variables.core.Variable
cause-exception : com.thoughtworks.xstream.converters.reflection.ObjectAccessException
cause-message : Cannot find class com.ur.view.variables.core.Variable
class : com.ur.view.variables.core.Variable
required-type : com.ur.view.variables.core.Variable
path : /Installation/Contributions/URCaps/Contributed[3]/Variable/variable
line number : 247
-------------------------------
cause-exception : com.ur.polyscope.persistence.UnableToConvertValue
cause-message : interface com.ur.view.variables.core.Variable: Cannot find class com.ur.view.variables.core.Variable : Cannot find class com.ur.view.variables.core.Variable
---- Debugging information ----
message : Cannot find class com.ur.view.variables.core.Variable
cause-exception : com.thoughtworks.xstream.converters.reflection.ObjectAccessException
cause-message : Cannot find class com.ur.view.variables.core.Variable
class : com.ur.view.variables.core.Variable
required-type : com.ur.view.variables.core.Variable
path : /Installation/Contributions/URCaps/Contributed[3]/Variable/variable
line number : 247
-------------------------------
class : com.ur.polyscope.installation.Installation
required-type : com.ur.view.variables.core.Variable
path : /Installation/Contributions/URCaps/Contributed[3]/Variable/variable
line number : 247
-------------------------------

```

Using ur-sdk 1.13.0 and ursim 5.12.4.

Similar problem to [Error while starting PolyScope at "com.ur.urcap.conveyortracking [79]" - #2 by urcaps.lorenscheit](https://forum.universal-robots.com/t/error-while-starting-polyscope-at-com-ur-urcap-conveyortracking-79/1616/2)  
Wonder if this has been addressed.