If you're going to install Visual Studio 2005 SP1 on a machine, running the Beta version of the same service pack (VS2005 SP1 Beta), you'll have to uninstall that first, otherwise this nasty message will prevent you from installing the release version. To uninstall the SP1 Beta, go to Control Panel and review installed updates:
- [Win XP] - Go to Add or Remove programs and check "Show Updates"
- [Win Vista] - Go to Programs, Programs and Features and choose "View Installed Updates"
The VS2005 Service Pack 1 should appear right under the Microsoft Visual Studio 2005. Select "Service Pack 1 Beta" and choose to uninstall it.
It will take a while for SP1 Beta to uninstall and perhaps you'll need your copy of Visual Studio 2005 installation CDs/DVD handy, just in case some old files are needed to reinstall... After setup program is done uninstalling, you can continue installing the release version of VS2005 SP1.