ROOT 6 for Windows?

are there any binaries available for ROOT 6 for Windows?
If not, are there instructions for building it?
The downloads webpage doesn’t mention this topic at all, unfortunately.

Hi Kilian,

ROOT 6 is not yet supported on Windows. The version of clang we are using internally is not fully compatible with the C++ Windows API. This should be fixed with the latest version of llvm/clang.

Cheers, Bertrand.

Hi Bertrand,

okay, thanks for letting me know. I’m currently tutoring a course that involves numerical simulations and we’ll be using ROOT. I was hoping I’d be able to use the latest and greatest ROOT version, but some of the students have Windows only on their notebooks, so ROOT 5 seems to be the safe option for now.

Would it be possible to add some text explaining the limited availability on Windows on the page?

(NB: The text on this download page seems to be out of sync with the downloads available below, it is mentioning “development, production and old” releases, but this separation is then not actually used. This is one of the first impressions a new ROOT user gets, so maybe worthwhile to update.)

Thanks again, and cheers,

Apologies for dredging up this old thread.

Since the writing of this a new version of Clang/LLVM (3.8.0) has been released. Does this version fix the incompatibilities?

We are very interested in ROOT 6 on Windows with the eventual goal of a MSVC x64 build. I have some time available to contribute to this goal. Is the best place to start the public git repository master branch, or is there some effort being made in someone’s private fork? Or perhaps I am absolutely crazy in believing this to be an achievable goal?

Any advice or guidance on this matter is appreciated.


Hi Tim,

The incompatibilities have been resolved since quite a while, and we are in the process of updating our version of llvm & clang, and until this is done, there is not much we can do…
Once this is done (once the new version will be integrated) you will be free to try it out by using the master branch of ROOT 6.
We first need to have cling working on Windows, and then we can work on ROOT itself.

Cheers, Bertrand.

Are there any news concerning ROOT6 on windows?
If work in this direction continues, what are the timelines? Will 64bit binaries be available?

Thank you,

Hi Andrey,

The status is still the same, but we made a lot of progress with cling on Windows though. And no, there will be no 64 bit binaries for quite some time (due to pointer to long conversion issues on Windows)

Cheers, Bertrand.

Thank you Bertrand!
I know it can be very difficult to estimate, but maybe some rough ETA? This month? 6 month? 1 year?
I am sure many developers, including myself, who use ROOT as a library in a multiplatform project would very much like to know.


Let’s say that it is foreseen to come this year… :wink:

Cheers, Bertrand.


64 bit binaries will be awesome once you’re able to release them. I’m excited

May I ask why you need 64 bit binaries?

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I need them very much too!
We use Root as a library in a simulation / scintillation event reconstruction package (ANTS2), developed using Qt framework.
Root and, specifically, TGeoManager is used for 3D navigation during particle and photon tracking. Half of our users run the package on Windows, but due to the 32 bits the available memory limits very much the amount of events which can be processed. Root is the only dependency which stops us from going 64 bit.


OK, thanks for the feedback!

Similar experiences here as well: 32-bit address space run out numerous times and ROOT was probably the only reason that prevented creation of 64-bit builds of the application (and another reasons prevented using something else than Windows).

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There is another strong reason:
Some broadly used CUDA libraries from NVidia are provided on Windows only for 64 bits.

Looks like a bad sign:
does not have a link to ROOT5 anymore!
How about Windows users?


This is indeed an error. We’ll check and correct it asap.

Cheers, Bertrand.


all the releases can be found here
That page shows the releases in the past 12 months, current month excluded. I’ll make sure the text is clearer.


Hi Danilo,
It is not a very good option to hide ROOT5 on the main download page while ROOT6 is not available for Windows.
For example, home page of our project gives the link to the “downloading-root” page, and now Windows
user will not find their download there.
The page with all releases is not a good option either - the ROOT5 versions are sorted by the number, and because of the buggy version numbers of 5.99, the most recent version is not apparent.
Could you please return ROOT5 back until ROOT6 is available for Windows?


I would like to repeat the request:
Could you please return ROOT5 back to “Download ROOT” page until ROOT6 is available for Windows?