Microsoft has made numerous changes to Windows Vista with the release of RC1. It has reworked the Network and Sharing Center to make it easier to use, improved the Internet Explorer web browser and reworked the Parental Control feature.

The User Account Control security feature, which has been criticized by beta testers because of its intrusiveness, has been significantly streamlined and presents far fewer prompts. In addition, overall performance improvements have been made possible by fine-tuning I/O of background services.

Microsoft also said it has substantially enlarged the driver pack to make it work better with a wider range of components and peripherals. In addition, Microsoft .Net Framework 3.0, previously called WinFX, is now installed by default. In Beta 2, it was not installed but was available as an add-on option. Because it is now part of the operating system, Microsoft said, programmers will be more willing to write to it.

Windows Vista application programming interfaces are locked with RC1 and will not change, so developers can begin writing Windows Vista-specific applications and utilities knowing that they will work on the shipping product, according to Microsoft.