Thanks for your detailed bug report! However, we are not relying on file locations (see this line), so something else must go wrong...

Can you please verify that your VS installation indeed contains the DIA stuff? Search for msdia within the VS20127 folder...

It seems the files are there.
https://gist.github.com/Farwaykorse/27e4d854e12b74ecf79a8f198c0929f0

For now I've tried repairing the installation and a second install using 2017 preview with a basic c++ workload.

Thanks! Could you please also search for e6756135-1e65-4d17-8576-610761398c3c (and maybe also
3bfcea48-620f-4b6b-81f7-b9af75454c7d) within your registry? Just in case: Use the regedit tool for this... If you do have findings: Are they located within a CLSID folder?

Explanation: We are using CLSIDs to instantiate the DIA COM objects - they should be made available through the registry. If you do not have any findings, the VS2017 installation has not added them to the registry for some reason. In that case, we will have to investigate the VS2017-only case a bit closer.

@NinjaCoder Thanks for adding that information! You say that it started on March 14th - does that mean that source locations worked before that date on VS2017 even without having VS2015 installed?

@Farwaykorse Can you confirm the problems with debugging tests?

I do have both keys. Both are located in CLSID folders.
But they point to non-existing locations of previous installs of VS.

e6756135-1e65-4d17-8576-610761398c3c points to:
C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\Packages\Debugger\msdia140.dll
3bfcea48-620f-4b6b-81f7-b9af75454c7d points to:
C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\Packages\Debugger\msdia120.dll

To make it more complex.
The VS2017 install does contain the file. At:
C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\Packages\Debugger\msdia140.dll
So I did a search for register entries with \msdia140.dll in the Data field. This yielded only references to locations in the (almost) empty directories below ..\Microsoft Visual Studio 14.0\...
I found no reference in the registry to the VS2017 version of the file.

By the way. The dll does work if I manually copy it to the referenced vs2015 location.

Debugging tests didn't ever produce unexpected errors for me.

@Farwaykorse Thanks for the update - kind of as expected. It looks like VS2017 doesn't register the DIA DLLs publically any more... We'll look into this and figure out a reliable way to locate and instantiate the DIA DLL in case only VS2017 is installed - stay tuned.

@NinjaCoder It looks like your debugging problem is not related to this bug - would you mind to open a new issue and copy over your logging stuff? Thanks!

Maybe this can help: https://github.com/microsoft/vs-setup-samples

Thanks! Your link might indeed be useful...

Until we have figured out a reliable way to instantiate the DIA com object on VS 2017, this registry patch should also provide a workaround without the need to copy dlls around. Change file ending to .reg and install - file locations should be found afterwards. The patch assumes the VS standard installation directory - adjust if needed.

Just confiming this registry patch is a working set (at least for the community edition of VS2017).

It's a documented breaking change in VS 2017.