After deploying a managed code application to a windows CE6 R3 device you get a deployment error something like:

Deploying ‘C:willVBProjectsCEAppbinDebugHelloWorld.exe’
Deploying ‘C:Program FilesMicrosoft Visual Studio 8SmartDevicesSDKCompactFramework2.0v2.0windowscediagnosticsSystem_SR_enu.cab’
Post-deploy error 0x00000001 returned after calling ‘Windowswceload.exe /noui WindowsSystem_SR_enu.cab’.
========== Build: 1

Visual Studio 2005 will attempt to download the .NET CF 2.0 cab file (System_SR_enu.cab) and automatically install  if the device does not already contain the  run time (however the OS dependencies for the .NET CF 2.0 must be included in the WinCE6 image). It appears that the version of .NET CF 2.0 included with Visual Studio 2005 SP1 is not compatible with the R3 release of Windows CE6. To fix the problem, shutdown all instances of Visual Studio 2005 and simply download and install .NET CF2.0 SP2:

http://www.microsoft.com/downloads/en/details.aspx?familyid=AEA55F2F-07B5-4A8C-8A44-B4E1B196D5C0&displaylang=en

Try again and everything should be fine.

A successful deployment should then look something like:

DeviceApplication1 -> C:Documents and SettingsXPMUserMy DocumentsVisual Studio 2005ProjectsDeviceApplication1DeviceApplication1binDebugDeviceApplication1.exe
—— Deploy started: Project: DeviceApplication1, Configuration: Debug Any CPU ——
Deploying ‘C:Program FilesMicrosoft.NETSDKCompactFrameworkv2.0windowscewce500armv4iNETCFV2.wce5.armv4i.cab’
Deploying ‘C:Documents and SettingsXPMUserMy DocumentsVisual Studio 2005ProjectsDeviceApplication1DeviceApplication1binDebugDeviceApplication1.exe’
Deploying ‘C:Program FilesMicrosoft.NETSDKCompactFrameworkv2.0windowscediagnosticsSystem_SR_enu.cab’
========== Build: 1 succeeded or up-to-date, 0 failed, 0 skipped ==========
========== Deploy: 1 succeeded, 0 failed, 0 skipped ==========