If you have the latest version of the Silverlight end user runtime installed, you may see the following error after installing Visual Studio 2010 RC:
[02/10/10,18:18:55] Microsoft Silverlight:  Error code 1502 for this component means "The event log file is full.
[02/10/10,18:18:55] Microsoft Silverlight:  Component Microsoft Silverlight returned an unexpected value.
[02/10/10,18:18:55] Microsoft Silverlight:  Return from system messaging: The event log file is full.
There are two versions of the Silverlight runtime: The end user runtime and the developer runtime which contains a managed debugging component that allows developers to debug their Silverlight applications.
Silverlight recently released an update on Microsoft Update to the runtime to support features you’ll see on the web broadcast of the Winter Olympic Games. Updates were released for both the end user and developer runtimes.
Visual Studio 2010 RC has a slightly older release of the dev runtime included. If only the end user runtime is installed, during VS installation, it detects that the managed debugging component is missing and attempts to install the dev runtime. However, because the newest end user runtime is already installed, installation fails. (And the error code is misinterpreted to mean that the event log is full.
This issue was recently fixed, but after the final build of VS2010 RC was released, so it will be in the RTM release. In the meantime…
If you’re not a Silverlight developer, go ahead and ignore this message. Your installation of Visual Studio is not affected.
If you are a Silverlight Developer, you can download and install the latest version of Silverlight 3 Developer Runtime or the Silverlight 4 Beta Developer Runtime so that you can debug your Silverlight projects.