After you update to a new version of the ComponentOne WinForms Edition, you start seeing C1 controls in the component tray and you are not able to select them on the Form. Otherwise, you see errors as in the image below wherein, clicking 'Ignore and Continue' option removes all controls from the Form.
Solution 1
The design-time layouts of WinForms controls are implemented in their Design dlls. If the WinForms suite is installed on the machine using the installer, these assemblies are automatically installed in the Global Assemly Cache. If you upgrade your controls using our installer, then also the Design dlls are placed correctly in GAC. However, if you decide to upgrade assembly references manually by downloading the files that contains assemblies only, please be aware that these two approaches do not install the Design assembly in your GAC automatically. So, to resolve this case, you should simply install the Design dlls manually in your GAC. These Design dlls are shipped with every release build of WinForms assemblies which you might have downloaded. If this still does not resolve the issue, please make sure that all references to C1 assemblies point to the latest version installed on the machine.
Solution 2
Just copy the same version of Design dll which you are using in the application, to folder where Visual Studio "devenv.exe" file exists. E.g. For VS.2010 --> C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE Close and open Visual Studio then. The issue will be resolved.