Several VS 2008 and Windows SDK users have reported that Intellisense stops working for XAML projects  after installing the Windows SDK for Windows Server 2008 and .NET Framework 3.5.

 The Windows SDK Team and the Visual Studio 2008 team has been able to repro the issue and the cause has been identified.  A Visual Studio registry value is being incorrectly reset after the Windows SDK is installed, causing this failure. 

 How to determine if  you are experiencing this issue

1.       Please review the article, Windows registry information for advanced users before using regedit.

2.       Using regedit, look at the key:  

·         On X86 machines: HKEY_CLASSES_ROOT\CLSID\{73B7DC00-F498-4ABD-AB79-D07AFD52F395}\InProcServer32

·         On X64 machines: HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{73B7DC00-F498-4ABD-AB79-D07AFD52F395}\InProcServer32

3.       If (Default) is empty you are experiencing this issue

 We suggest two workarounds: repair Visual Studio 2008 or register TextMgrP.dll manually. 

Repair Visual Studio 2008:

1.       From the Start button, open the  Control Panel

2.       Click on Program and Settings (Add/Remove Programs on non-Vista machines)

3.       Click to select Visual Studio 2008 and click Change (at the top of the window)

4.       When the change dialog box launches, select Repair 

 Register TextMgrP.dll manually

On an X86 machine:

1.       Open a Windows CMD window as an Administrator (On Vista: Start, All Programs, Accessories, right-click on command prompt and  choose to Run as Administrator)

2.  Type: regsvr32 "%CommonProgramFiles%\Microsoft Shared\MSEnv\TextMgrP.dll”

 

On an X64 machine:

1.       Open a Windows CMD window as an Administrator (On Vista: Start, All Programs, Accessories, right-click on command prompt and  choose to Run as Administrator)

2.  Type: regsvr32 "%CommonProgramFiles(X86)%\Microsoft Shared\MSEnv\TextMgrP.dll”

 

 Restart Visual Studio and Intellisense should be working correctly again.