Trying the trial of the Telerik suite for WinForms in Visual Studi 2013, but any time I try to make new Telerik winforms projects I get the same error message when trying to open the form: 

   To prevent possible data loss before loading the designer, the following errors must be resolved:              1 Error         Why am I seeing this page?             Value cannot be null. Parameter name: instance              Instances of this error (1)   1.   Show Call Stack   at System.ComponentModel.TypeDescriptor.AddAttributes(Object instance, Attribute[] attributes)at Microsoft.VisualStudio.Design.VSDesignSurface.CreateDesigner(IComponent component, Boolean rootDesigner)at System.ComponentModel.Design.DesignerHost.AddToContainerPostProcess(IComponent component, String name, IContainer containerToAddTo)at System.ComponentModel.Design.DesignerHost.PerformAdd(IComponent component, String name)at System.ComponentModel.Design.DesignerHost.System.ComponentModel.Design.IDesignerHost.CreateComponent(Type componentType, String name)at System.ComponentModel.Design.Serialization.DesignerSerializationManager.CreateInstance(Type type, ICollection arguments, String name, Boolean addToContainer)at System.ComponentModel.Design.Serialization.DesignerSerializationManager.System.ComponentModel.Design.Serialization.IDesignerSerializationManager.CreateInstance(Type type, ICollection arguments, String name, Boolean addToContainer)at System.ComponentModel.Design.Serialization.TypeCodeDomSerializer.Deserialize(IDesignerSerializationManager manager, CodeTypeDeclaration declaration)at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager manager)at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager)at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.DeferredLoadHandler.Microsoft.VisualStudio.TextManager.Interop.IVsTextBufferDataEvents.OnLoadCompleted(Int32 fReload)     

Hi Ralisa,

 It helped me. Thanks

Thank You...It worked for me as well

Perfect solution. Thanks

This didn't work for me. My project was working fine in VS2017. I used control panel to install the tools to VS 2013. Now my 2017 project won't load/compile correctly. I get numerous errors like the one below. I tried adding the UI.Design and even completely reinstalling the suite for 2017. No luck.

 

SeverityCodeDescriptionProjectFileLineSuppression State

ErrorCS1705Assembly 'Telerik.WinControls.GridView' with identity 'Telerik.WinControls.GridView, Version=2017.3.1017.40, Culture=neutral, PublicKeyToken=5bb2a467cbec794e' uses 'Telerik.WinControls, Version=2017.3.1017.40, Culture=neutral, PublicKeyToken=5bb2a467cbec794e' which has a higher version than referenced assembly 'Telerik.WinControls' with identity 'Telerik.WinControls, Version=2017.3.912.40, Culture=neutral, PublicKeyToken=5bb2a467cbec794e'CredMan

Hi Jeff,

Thank you for contacting us. 

I would like to ask you to carefully check the references to all Telerik controls in your project and make sure that they are the same version considering the suffix as well (.20 or .40). Better yet, you can remove all references and add them anew by using the DLLs from your latest installation. If the license.licx file exist, you need to delete it (Visual Studio Project >> Properties >> Licenses.licx) . After that, you should rebuild your project, close Visual Studio and open it again to make sure that no references are kept in the memory by Visual Studio.  

I hope this information helps. Should you have further questions I would be glad to help.

Regards,
Ralitsa
Progress Telerik

Hi Ralitsa,

I recently removed all the dlls and added them in. They are all version .20 and the issue still exists.

Thanks.

Hello Jeff,

Thank you for writing back. 

The observed exception is shown when the referenced assemblies are different or the license.licx is not deleted. Once you have checked and update the referenced assemblies in your application, I can suggest you deleting the license file. You can follow the steps below: 
1. Run Visual Studio and open your project
2. Close all opened forms. Delete license.licx file (see attached image) 
3. Save the changes and close the Visual Studio
4. Open the project again and rebuild. 

Let me know if you have any other questions.

Regards,
Ralitsa
Progress Telerik

Thank you in advance for all the help.

I also tried the suggestions listed before, but am experiencing the same problems as Jeff.

Using VS2017, I deleted the license file, removed/verified all .dll are same versions, and cleared any resident GAC entries.

 

Just so it's clear.... My error is the following call stack in designer:

Value cannot be null. Parameter name: instance



Instances of this error (1)

1. Hide Call Stack
at System.ComponentModel.TypeDescriptor.AddAttributes(Object instance, Attribute[] attributes)
at Microsoft.VisualStudio.Design.VSDesignSurface.CreateDesigner(IComponent component, Boolean rootDesigner)
at System.ComponentModel.Design.DesignerHost.AddToContainerPostProcess(IComponent component, String name, IContainer containerToAddTo)
at System.ComponentModel.Design.DesignerHost.PerformAdd(IComponent component, String name)
at System.ComponentModel.Design.DesignerHost.System.ComponentModel.Design.IDesignerHost.CreateComponent(Type componentType, String name)
at System.ComponentModel.Design.Serialization.DesignerSerializationManager.CreateInstance(Type type, ICollection arguments, String name, Boolean addToContainer)
at System.ComponentModel.Design.Serialization.DesignerSerializationManager.System.ComponentModel.Design.Serialization.IDesignerSerializationManager.CreateInstance(Type type, ICollection arguments, String name, Boolean addToContainer)
at System.ComponentModel.Design.Serialization.TypeCodeDomSerializer.Deserialize(IDesignerSerializationManager manager, CodeTypeDeclaration declaration)
at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager manager)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager)
at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.DeferredLoadHandler.Microsoft.VisualStudio.TextManager.Interop.IVsTextBufferDataEvents.OnLoadCompleted(Int32 fReload)

Just so it's more clear.... It's the error preventing the designer from loading.

Attaching stack trace....

 

Hello, John,  

Thank you for writing.  

Could you please try to create a new project and test whether the designer will be opened? Further, I can suggest you to uninstall all available versions of the Telerik UI for WinForms suite on your machine. Then, install the desired version (latest version is recommended). Delete the license file and update the references with the ones from the fresh installation.

If you are still experiencing any further difficulties, it would be greatly appreciated if you submit a support ticket and provide your sample project. Thus, we would be able to investigate the precise case and assist you further. 

I hope this information helps.  
 
Regards,
Dess
Progress Telerik

Ok. I found out why I was having problems. There are/were 2 issues....

First, designer errors using regular forms was caused by multiple problems (different DLL versions (GAC vs. local reference) and problems with AutoGenerateBindingRedirect). This was solved using the provided idea of absolutely killing all Telerik controls and installs, manually removing any remaining orphaned Telerik GAC entries(from older installs not using MSI which is what was causing a lot of issues), flushing all Telerik project references and license files, kill any binding overrides/redirects, then go back into solution and manually reference the DLLs not using the MSI to re-install.

Second problem is totally my fault for not paying attention.... I'm using VS2017 and attempting to use Telerik Reporting which doesn't have (as far as I can tell) VS2017 native support (goes up to VS2015), so when I tried to open an older report file it threw the form design error as well (but a slightly different one).

However, as usual, Telerik support is responsive and helpful. Many thanks. - John

Hello, John, 

Thank you for writing back. 

I am glad that the problem you were facing is now resolved. A clean installation of the Telerik UI for WinForms suite and referring these assemblies usually fixes the designer problems because the design time uses the references in GAC.

If you have any additional questions, please let me know. 

 Regards,
Dess
Progress Telerik

When am trying to open RadForm getting an error 

I tried with above process but unable to resolve error.

 

at
Microsoft.VisualStudio.WinForms.RemoteClient.Loader.RemoteCodeDomDesignerLoader.EnsureDocument(IDesignerSerializationManager
manager)
at
Microsoft.VisualStudio.WinForms.RemoteClient.Loader.RemoteCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager
manager)
at
Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager
serializationManager)
--- End of stack trace from previous location where
exception was thrown ---
at
Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager
serializationManager)
at
Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.DeferredLoadHandler.Microsoft.VisualStudio.TextManager.Interop.IVsTextBufferDataEvents.OnLoadCompleted(Int32
fReload)

Hello, Jagdeesh,      

I would like to ask you to carefully check the references to all Telerik controls in your project and make sure that they are the same version considering the suffix as well (.20 or .40). Better yet, you can remove all references and add them anew by using the DLLs from your installation. Delete the license.licx file. After that, you should rebuild your project, close Visual Studio and open it again to make sure that no references are kept in the memory by Visual Studio.  

However, if you are still experiencing any further difficulties, I would kindly ask you submit a support ticket from your account and provide a sample project demonstrating the undesired behavior that you are facing. Thus, our support staff would be able to investigate the precise case and provide further assistance. Thank you in advance.

I hope this information helps.

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik