Recently while working with SharePoint object model
to retrieve items from a SharePoint document library, I face this error: "One or more field types are not installed properly. Go to the list settings page to delete these fields."
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I was retrieving items based on the SharePoint column internal name. I was using this article
to retrieve the internal name of a SharePoint column name. I retrieve the column name as "First%5Fx0020%5FName". And my SharePoint object model code as:
String firstname = "Fewlines4Biju";
SPQuery objquery = new SPQuery();
objquery.Query = "<Where><Eq><FieldRef Name='First%5Fx0020%5FName' /><Value Type='Number'>" + firstname + "</Value></Eq></Where>";
Here I got the error when the above code executed.
Actually Here problem is with the %5F which internally represents underscore (_). So when I changed the code like below it worked.
objquery.Query = "<Where><Eq><FieldRef Name='First_x0020_Name' /><Value Type='Number'>" + firstname + "</Value></Eq></Where>";
This will resove the error.