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Windows 10 Shutdown error

Bronze Super Contributor
Posts: 1,284
Country: USA

Windows 10 Shutdown error

After installing Win10 and restarting I am getting this error when I quit ACT. 


I have NO ADD-ONS installed



System.NullReferenceException was unhandled
Message: An unhandled exception of type 'System.NullReferenceException' occurred in Act.UI.Core.dll
Additional information: Object reference not set to an instance of an object.


Object reference not set to an instance of an object.



System.NullReferenceException: Object reference not set to an instance of an object.
at Act.UI.Core.Explorer.MarkVisibleBars()
at Act.UI.ActApplication.Quit()
at Act.UI.ActApplication.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)












Copper Super Contributor
Posts: 86
Country: United_Kingdom

Re: Windows 10 Shutdown error

Hi Jim,


This is a known issue and is currently being investigated by our development team.


Please see the following knowledgebase article:


Known issues and workarounds for using Act! v17 and later with Windows 10


There is no workaround at this time, however we're not aware that it's causing any issues so our current advice is to ignore the error.


Please see the stickied post at the top of this forum regarding Windows 10 compatibility.

Unless the post is specifically about using the SDK with Windows 10 I would prefer it if posts were made in the product forums instead.


Kindest regards,




Unfortunately I no longer work for Swiftpage International. Please do not send any queries to this account.
Copper Contributor
Posts: 123
Country: Canada

Re: Windows 10 Shutdown error

I'm also receiving this error, is there any update on this?