title: Sharepoint custom field type
body: <p>I have created a custom field type which inherits directly from SPField but when I try to add the field to a list I get the following error: </p>
  
  <p>One or more field types are not installed properly. Go to the list settings page to delete these fields.   at Microsoft.SharePoint.Library.SPRequestInternalClass.AddField(String bstrUrl, String bstrListName, String bstrSchemaXml, Int32 grfAdd) 
     at Microsoft.SharePoint.Library.SPRequest.AddField(String bstrUrl, String bstrListName, String bstrSchemaXml, Int32 grfAdd)</p>
  
  <p>I have looked at the log file and there is no helpful information as to what is causing the problem and I have attached the debugger to the process and it exits after the base constructor for the field type has been called.</p>
  
  <p>Does anyone know what could be going wrong from this error? Many thanks in advance.</p>