You may notice this error on your K2 Environment:
"Additional: FileUtility.PurgeIsolatedStore: = Vxsna9cx5
System.IO.IsolatedStorage.IsolatedStorageException: Unable to delete, directory not empty or does not exist.
at System.IO.IsolatedStorage.IsolatedStorageFile.DeleteDirectory(String dir)
at SourceCode.Forms.AppFramework.FileUtility.PurgeIsolatedFiles(TimeSpan purgeAge)"
You may notice this error message within your Windows Event Viewer log files and you may even notice that a folder called "IsolatedStorage" is filling up the temporary folders on your environment.
This is a known issue within the K2 Product, and it has been resolved from K2 4.7 and onwards.
However, there is a codefix for 4.6.11. Please log a new support ticket to request the latest K2 SmartForms patch.