From: Atanu Acharya (
Date: Wed Feb 08 2023 - 15:39:47 CST

Hi Pol,
   I recently encountered the same OSPRay problem on Windows 11. Johnís suggestion worked for me.

Hope this helps,

From: <> on behalf of Pol Garcia-Segura <>
Date: Wednesday, February 8, 2023 at 4:15 PM
To: Axel Kohlmeyer <>
Cc: <>
Subject: Re: vmd-l: VMD on Windows 11
Dear Axel,

I already tried this, but I get this error message when trying to open VMD:
#osp: INITIALIZATION ERROR --> #osp:api: could not find module initializer
#osp: INITIALIZATION ERROR --> Could not find device of type: default.
Make sure you have the correct OSPRay libraries linked.
#osp: INITIALIZATION ERROR --> OSPRay not yet initialized (most likely this
means you tried to call an ospray API function before first calling
ospInit())(pid 1768)

I tried to run this (as suggested by previous VMD-L mailing list messages):

PS C:\Program Files\VMD> set VMDNOOSPRAY=1
PS C:\Program Files\VMD> .\vmd.exe

But still got the same error..

Do you know how can I solve it?

Thank you,


On Wed, Feb 8, 2023 at 7:57 PM Axel Kohlmeyer <<>> wrote:

there *is* a 64-bit Windows build. You just have to download and install the latest "alpha" version.
"Alpha" is a relative term here. Most of VMD has been stable and reliable for most people.
But there have been issues with some of the GUI libraries that VMD is using on 64-bit for macOS and Windows, specifically
and also those are not always 100% compatible with high-DPI screen (what is called "Retina" on macOS) because GUI element size settings were pixel based.

If you are affected too much by Windows specific issues, you can consider installing the Windows Subsystem for Linux (WSL2) and then download and install the Linux version of VMD (but you likely still want to download the alpha version, since version 1.9.3 dates from 2016 and that is in computer terms the stone age).


On Wed, Feb 8, 2023 at 1:44 PM Pol Garcia-Segura <<>> wrote:

I was wondering if you plan to update VMD so it can be used on Windows 11 x64. So far, I've managed to use the x32 version for Windows 10. But it has a problem in detecting the available memory of the system. Therefore, I cannot run analyses because I run out of memory.
Is there anything I can do?

Thank you,


Dr. Axel Kohlmeyer<>;!!DZ3fjg!50gzU97t3o6x9hG0P8jG__r17hO_Bxlgn5D-OFeNjBNQg5nZbM2zrIG354JFdRxo9qWxI4AOIjcRCgKg1ug$ <;!!DZ3fjg!_ZCyjspUle8l6YUgAUVoLEdASVurYDG_1dYEgKoR_QLZPDG24E5phFwYjzFWX7HSVjUyvO8WkuXPxWwlVtM$>
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.