Telerik SPRadScheduler appoitments can be populated at client-side via web service. This improves performance by minimizing the HTML output and removing the need of a page refresh.
In this mode RadScheduler does not postback to the page and the appointments are rendered on the client.
 

 Error ‭[2]‬

 
Web Part Error: One of the properties of the Web Part has an incorrect format. Microsoft SharePoint Foundation cannot deserialize the Web Part. Check the format of the properties and try again.

Error Details:
[WebPartPageUserException: One of the properties of the Web Part has an incorrect format. Microsoft SharePoint Foundation cannot deserialize the Web Part. Check the format of the properties and try again.]
  at Microsoft.SharePoint.WebPartPages.WebPart.ParseXml(XmlReader reader, Type type, String[] links, SPWeb spWeb)
  at Microsoft.SharePoint.WebPartPages.WebPart.ParseCompressed(SPWebPartManager manager, XmlNamespaceManager xmlnsManager, Byte[] personal, Byte[] global, String[] links, Type type, SPWeb spWeb)
  at Microsoft.SharePoint.WebPartPages.BinaryWebPartDeserializer.LoadInitialWebPart()
  at Microsoft.SharePoint.WebPartPages.BinaryWebPartDeserializer.Deserialize()
  at Microsoft.SharePoint.WebPartPages.SPWebPartManager.CreateWebPartsFromRowSetData(Boolean onlyInitializeClosedWebParts)

[Exception: Cannot create XmlSerializers for this Web Part.]
  at Microsoft.SharePoint.WebPartPages.TypeCacheEntry.get_FailedXmlSerializer()
  at Microsoft.SharePoint.WebPartPages.TypeCacheEntry.get_XmlSerializer()
  at Microsoft.SharePoint.WebPartPages.WebPart.ParseXml(XmlReader reader, Type type, String[] links, SPWeb spWeb)
 

 Error ‭[1]‬

 
Web Part Error: One of the properties of the Web Part has an incorrect format. Microsoft SharePoint Foundation cannot deserialize the Web Part. Check the format of the properties and try again.

Error Details:
[WebPartPageUserException: One of the properties of the Web Part has an incorrect format. Microsoft SharePoint Foundation cannot deserialize the Web Part. Check the format of the properties and try again.]
  at Microsoft.SharePoint.WebPartPages.WebPart.ParseXml(XmlReader reader, Type type, String[] links, SPWeb spWeb)
  at Microsoft.SharePoint.WebPartPages.WebPart.ParseCompressed(SPWebPartManager manager, XmlNamespaceManager xmlnsManager, Byte[] personal, Byte[] global, String[] links, Type type, SPWeb spWeb)
  at Microsoft.SharePoint.WebPartPages.BinaryWebPartDeserializer.LoadInitialWebPart()
  at Microsoft.SharePoint.WebPartPages.BinaryWebPartDeserializer.Deserialize()
  at Microsoft.SharePoint.WebPartPages.SPWebPartManager.CreateWebPartsFromRowSetData(Boolean onlyInitializeClosedWebParts)

[Exception: Cannot create XmlSerializers for this Web Part.]
  at Microsoft.SharePoint.WebPartPages.TypeCacheEntry.get_FailedXmlSerializer()
  at Microsoft.SharePoint.WebPartPages.TypeCacheEntry.get_XmlSerializer()
  at Microsoft.SharePoint.WebPartPages.WebPart.ParseXml(XmlReader reader, Type type, String[] links, SPWeb spWeb)