i see that my post is missing some info : 

Click ok in error message, the upper menu in Studio freeze. Only option is to force quit the application.
PLease help,
Best regards.

Installed versions (in a RDS Server 2022 environment):
Trados Studio:
Studio 2024 18.0.1.2259
Plugins:
Trados Data Protection Suite v. 4.0.1.0
TMAnonymizer 5.0.0.2024

and some extra details : 

<SDLErrorDetails time="20-2-2025 16:26:44">
<ErrorMessage>De objectverwijzing is niet op een exemplaar van een object ingesteld.</ErrorMessage>
<Exception>
<Type>System.NullReferenceException, mscorlib, Version=4.0.0.0, Culture=neutral, Public token removed.
<HelpLink />
<Source>Sdl.Desktop.Platform</Source>
<HResult>-2147467261</HResult>
<StackTrace><![CDATA[   bij Sdl.Desktop.Platform.AbstractDockingView.SaveState(ISettingsGroup settings)
   bij Sdl.Desktop.Platform.Implementation.StudioWindow.SaveState()
   bij Sdl.Desktop.Platform.Implementation.StudioWindow._form_Closed(Object sender, EventArgs e)
   bij System.EventHandler.Invoke(Object sender, EventArgs e)
   bij System.Windows.Forms.Form.OnClosed(EventArgs e)
   bij System.Windows.Forms.Form.WmClose(Message& m)
   bij System.Windows.Forms.Form.WndProc(Message& m)
   bij Sdl.Platform.UI.StudioWindowForm.WndProc(Message& message)
   bij System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   bij System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   bij System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)]]></StackTrace>
</Exception>
<Environment>
<ProductName>Trados Studio</ProductName>
<ProductVersion>Studio18</ProductVersion>
<EntryAssemblyFileVersion>18.0.1.2259</EntryAssemblyFileVersion>

<ServicePack>NULL</ServicePack>
<OperatingSystemLanguage>1043</OperatingSystemLanguage>
<CodePage>1252</CodePage>
<LoggedOnUser><< removed >></LoggedOnUser>
<DotNetFrameWork>4.0.30319.42000</DotNetFrameWork>
<ComputerName><< removed >></ComputerName>
<ConnectedToNetwork>True</ConnectedToNetwork>
<PhysicalMemory>16776136 MB</PhysicalMemory>
</Environment>
</SDLErrorDetails>

Ennio Ghezzi 

The easiest way to get rid of this error is to reset Trados Studio.

To do so:

• delete the folder C:\Users\%username%\AppData\Roaming\Trados\Trados Studio\Studio18
• delete the folder C:\Users\%username%\AppData\Roaming\Trados\Trados Studio\18

This should allow you to start Trados Studio. Now do this:

• in Editor go to View and Reset window layout
• go to File -> Setup -> Manage user profiles and reset the user profile

This should stabilize Trados Studio for the future.

As you deleted the folders, all plugins will now be gone. Install the necessary plugins ONLY via Add-ins menu in Trados Studio. Also your adaptations of TS GUI and keyboard shortcuts will be gone. Adapt all the parameters as needed, then go again to File -> Setup -> Manage user profiles and save a copy of your current user profile in a separate folder. This way you will be able to recreate your settings in the future.

Thanks Jerzy,

I followed your answer, unfortunately I still have the error, even with ONLY the Trados Data Protection Suite plugin (v.4.0.1.0) enabled via the add-ins menu.

Hi Ennio Ghezzi ,

We raised an item for Development to look into it,

Once I have news, I'll post it here.

Thank you,

Regards,

Oana

Thanks Oana,

Can u give me an estimation when Development will answer to you?

Best regards,

Ennio

For the context / priorities : this issue affects all our end users.

I get the same error when I click on the option "TradosTM Anonymizer" in the lower left corner, and after clicking OK on the popup my ribbon and menu options are also unresponsive.

Thanks Alex to let me know. I am still waiting for an answer from Oana. We use Trados version 18.0.1.2259 in combination with Windows11 machines. I wonder if it is an permission issue, possibly the plugin doesn't get the necessary permissions to make modifications on the machines. But strangely any UAC requests do not pop up (which we do not allow for users).