When a large number of items is going to be published, the publishing process can be unexpectedly interrupted due to a low value of the Publishing.TimeBeforeStatusExpires setting.
The message in the publish dialog:
The publishing process was unexpectedly interrupted.
The error stack trace from the log file:
Application error.
Exception: System.Web.HttpUnhandledException
Message: Exception of type 'System.Web.HttpUnhandledException' was thrown.
Source: System.Web
at System.Web.UI.Page.HandleError(Exception e)
...
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
Nested Exception
Exception: System.Reflection.TargetInvocationException
Message: Exception has been thrown by the target of an invocation.
Source: mscorlib
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
...
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
Nested Exception
Exception: System.Exception
Message: The publishing process was unexpectedly interrupted.
Source: Sitecore.Client
at Sitecore.Shell.Applications.Dialogs.Publish.PublishForm.CheckStatus()