Delphi 2007 x Windows 10 - Error on opening project

You need to copy some files in your old Windows folder to the new one. After that projects open again.

The needed files are these :

C:\windows\Microsoft.NET\Framework\v2.0.50727\Borland.Common.Targets
C:\windows\Microsoft.NET\Framework\v2.0.50727\Borland.Cpp.Targets
C:\windows\Microsoft.NET\Framework\v2.0.50727\Borland.Delphi.Targets
C:\windows\Microsoft.NET\Framework\v2.0.50727\Borland.Group.Targets

Just copy them from the older Windows folder ( C:\Windows.old\Microsoft.NET\Framework\v2.0.50727\ ) to the new one.

I suspect that you've done an in-place upgrade of Windows. That is probably not compatible with your Delphi installation. Specifically the msbuild target files that you identified in your answer.

But there may well be more issues than this. I recommend performing a repair install of your Delphi. I believe that will bring the Delphi installation into line with the new OS. If you are at all paranoid about in-place upgrades and repair installs then you might contemplate a full Delphi re-installation.

As I was told to make my comment into an answer:

I had the same problem after the Win10 anniversary update. Here too the files are found in c:\Windows.old. As already listed by others, the files are

• C:\Windows.old\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Borland.Common.Targets
• C:\Windows.old\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Borland.Cpp.Targets
• C:\Windows.old\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Borland.Delphi.Targets
• C:\Windows.old\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Borland.Group.Targets

They need to be copied to their corresponding directory in c:\Windows.

You should note however that the Windows.old directory is automatically deleted after a couple of days! For the initial Win10 this seemed to be 28 days, for the anniversary update I was told it's only 10 days! I don't know about newer versions, though.