Created Unassigned: Store must be open for this operation [9495]

I am creating an excel file in excess of 40MB using the .net 4.5.1 framework with ClosedXML for .Net Framework 4.0. I save and reopen the file to append every 10000 rows to conserve memory. Is there a workaround for the following error or should i revert to .net 3.5?

System.ObjectDisposedException: Store must be open for this operation.
at System.IO.IsolatedStorage.IsolatedStorageFileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, IsolatedStorageFile isf)
at MS.Internal.IO.Packaging.PackagingUtilities.SafeIsolatedStorageFileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, ReliableIsolatedStorageFileFolder folder)
at MS.Internal.IO.Packaging.PackagingUtilities.CreateUserScopedIsolatedStorageFileStreamWithRandomName(Int32 retryCount, String& fileName)
at MS.Internal.IO.Packaging.SparseMemoryStream.EnsureIsolatedStoreStream()
at MS.Internal.IO.Packaging.SparseMemoryStream.SwitchModeIfNecessary()
at MS.Internal.IO.Packaging.SparseMemoryStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at MS.Internal.IO.Packaging.CompressEmulationStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at MS.Internal.IO.Packaging.CompressStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at MS.Internal.IO.Zip.ProgressiveCrcCalculatingStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at MS.Internal.IO.Zip.ZipIOModeEnforcingStream.Write(Byte[] buffer, Int32 offset, Int32 count)
at System.Xml.XmlUtf8RawTextWriter.FlushBuffer()
at System.Xml.XmlUtf8RawTextWriter.WriteElementTextBlock(Char* pSrc, Char* pSrcEnd)
at System.Xml.XmlUtf8RawTextWriter.WriteString(String text)
at System.Xml.XmlWellFormedWriter.WriteString(String text)
at DocumentFormat.OpenXml.OpenXmlElement.WriteTo(XmlWriter xmlWriter)
at DocumentFormat.OpenXml.OpenXmlCompositeElement.WriteContentTo(XmlWriter w)
at DocumentFormat.OpenXml.OpenXmlElement.WriteTo(XmlWriter xmlWriter)
at DocumentFormat.OpenXml.OpenXmlCompositeElement.WriteContentTo(XmlWriter w)
at DocumentFormat.OpenXml.OpenXmlElement.WriteTo(XmlWriter xmlWriter)
at DocumentFormat.OpenXml.OpenXmlCompositeElement.WriteContentTo(XmlWriter w)
at DocumentFormat.OpenXml.OpenXmlElement.WriteTo(XmlWriter xmlWriter)
at DocumentFormat.OpenXml.OpenXmlCompositeElement.WriteContentTo(XmlWriter w)
at DocumentFormat.OpenXml.OpenXmlPartRootElement.WriteTo(XmlWriter xmlWriter)
at DocumentFormat.OpenXml.OpenXmlPartRootElement.SaveToPart(OpenXmlPart openXmlPart)
at DocumentFormat.OpenXml.Packaging.OpenXmlPackage.SavePartContents()
at DocumentFormat.OpenXml.Packaging.OpenXmlPackage.Dispose(Boolean disposing)
at DocumentFormat.OpenXml.Packaging.OpenXmlPackage.Dispose()
at ClosedXML.Excel.XLWorkbook.CreatePackage(String filePath, SpreadsheetDocumentType spreadsheetDocumentType)...