If you’re migrating a VS project over to VS 2010 Beta1 and you are calling code that is passing Evidence objects to the runtime expecting security policy resolution, or if you’re using a permission Deny , you may run into the following exception: NotSupportedException...

We recently had a question about how to get more information than an exception’s type provides. The developer was trying to copy a file and didn’t know why the copy was failing. File copies can fail for many reasons, almost all of them what Eric Lippert...

Grant Richins has a post on the CLR Code Generation team blog that covers the work done to improve the x64 JIT to honor the "tail." instruction prefix, thereby making functional languages like F# more viable. You can find the full post here .

Shawn Farkas, CLR security developer, has started a cool series of posts on what’s new in .NET Framework 4 security. If you’re doing any work with or have scenarios involving partially trusted code, you’ll want to take a look. Topics include sandboxing...

For .Net Framework 4, we decided to remove the dependency on caspol and the policy levels and make things simpler. With this change, the default grant-set for assemblies is now FullTrust unless the host (such as InternetExplorer) decides to load them...

Update: The information in this blog post applies to pre beta-1 behavior and is not applicable to beta 2 and RTM. We will have more posts and documentation on this subject as we get closer to RTM. This section covers the most common in-process side...

One of the new features in CLR 4 is In-Process Side-by-side (Inproc SxS) – a feature that lets you use multiple versions of .NET in the same process. For applications that use add-ins (particularly COM add-ins), in-proc SxS lets us provide a level of...