Introduction :
SharePoint 2010 list definition can be created using Visual studio.
It is a xml file in which we can provide unique GUID, display name, Static name and more attributes.
In SharePoint GUID's are unique.
Suggestion :
Before use following solution take care of some points I mentioned below.
1] You are referring tag "
FieldRef" it means you are using existing column. which may be Site column/column from content Type/Predefine column for specific purpose by SharePoint.
2] Adding reference of improper GUID wont work if you are look for existing column.
Solution :
1] Each list column has unique id to create them Go to
Visual Studio 2010 SharePoint project => Tool => Create GUID => select Registry format =>
Click New GUID => Click Copy => Past it at desired location
Now you have new GUID.
In case you are looking for create definition from scratch follow below articles.
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