Who is this article for?

Users encountering the error.

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In the Action Tracker screen you may encounter an error message "Object reference not set to an instance of an object." referencing a stack trace at Pentana.Tng.UI.Smart.Common.HierarchyMatrixChangeHeadersCommand._Closure$__19-0._Lambda$__0().

This article provides a workaround to the issue.

1. Issue

On the Action Tracker screen you may encounter this error.

When you copy and paste the content into another application, you will see the error text:

Universal Time: (2025-09-18 10:30:55) Local Time: (2025-09-18 12:30:55) TimeZone: (02:00:00 DST)
Version: 6.0.1.8
EXCEPTION: NullReferenceException
message: Object reference not set to an instance of an object.
source: Pentana.Tng.UI.Smart.Common
target: Void _Lambda$__0()
stack: at Pentana.Tng.UI.Smart.Common.HierarchyMatrixChangeHeadersCommand._Closure$__19-0._Lambda$__0()
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

This is known to affect versions up to v6.0.1.8.

2. Workaround

The workaround is to clear your local settings. This will clear your current preferences, so make sure you check in any checked out audits or reserved documents prior to doing this.