GraphViz 2.38 does not recognize png ? (Python Anaconda / Windows)


I work with IPython (Py 2.7) / Anaconda (32 bit) on a Windows 7 PC. I am not very knowledgeable at all about IPython or GraphViz; I follow a video series which explains how to simulate poker hands w/ IPython, which is not necessarily intended for programmers. It uses GraphViz 2.38 to display certain results.

I get the following error in my notebook:

i.e. format "png" is not recognized. I already tried de-installing GraphViz and installing again. The error message is truncated, for some reason, so I don't even know what the full error says.

I first posted my problem in a Python forum, where I was told to try $ dot -Tpng in the Windows command shell:

That, apparently, means that it is not a Python problem, but specifically a GraphViz problem; that's why I was told to ask my question here.

Next, I tried "dot -v", and, since that one advised to run "dot -c", I did that:

But "dot -v" once more after that resulted in the same message as before.

I hope that someone can make sense of that - thanks for any input already !

P.S. I don't know why the inserted images (screenshots) don't work, so I attach them as files as well.

001.jpg133.76 KB
002.jpg28.75 KB
003.jpg76.5 KB

The Graphviz layout programs

The Graphviz layout programs rely on plug-ins for layout and rendering. To facilitate finding and loading these, dot expects to find a file called config6 in the Graphviz bin directory. This file is supplied as part of the Windows package. According to your .jpg files, Graphviz is installed in

C:\Program Files (x86)\Graphviz2.38

so check in C:\Program Files (x86)\Graphviz2.38\bin for the config6 file. It should be about 3569 bytes in size. Normally, you can recreate it by running dot -c. It appears you tried this and it still didn't work. This could be because you don't have permission to write in C:\Program Files (x86)\Graphviz2.38\bin or something else is happening. First check if you write permissions, but dot -c should produce an error message if you can't write there. Try running dot -v -c. This will create a trace telling you what plugins are found and where the config6 file is being placed.

Hi, I posted a reply two


I posted a reply two days ago, but it seems like it didn't get through somehow, so again:

I tried to google "check if I have write permission Windows 7" and similar, but couldn't find how to do that, but you hinted that -c should produce an error message anyway. I apparently do have the Config6 file, with exactly the right size, and I did dot -v -c as well, see here:

Does this help at all ? Thanks a lot; I'm still looking forward to any ideas :)

Hi, thank you ! I tried a to

Hi, thank you !

I tried a to google how to check if I have writing permissions or not ("check if i have write permission windows 7" etc.), but tbh, I could not find anything that explains this, but since you say that dot -c should produce an error message, I reply anyway: I could find the config6 file, and also did dot -v -c.

Result is as in this screen shot:

Does this help in any way ?

Again, thanks for the input !!

At this point, I am at a

At this point, I am at a loss. The config6 is there, dot is finding it in the right directory, and you re-generated it. As a check, would you please post the config6 so that I can verify its contents? Thanks.

Hi, sure ! For some reason,

Hi, sure ! For some reason, it seems that I could attach files in my OP, but not in the reply here anymore. The GraphViz FAQ about attaching files says I have to include the title to a "wiki page" in brackets in order to attach files - which seems to be like I have to start another thread in order to attach the file and then link to it here ? Not sure, tbh, so I uploaded the config6 file here on, it will be hosted there for 7 days:

Hope that serves its purpose. Thanks again !


P.S. If a mod wishes to upload the file in a way that follows the standard routine of posting files here, very welcome to fix the post, but I hope that anyone interested in helping with this issue can also easily download the file with the link I gave, and that the 7 days of storage will be sufficient.

Here is the user's config6

Here is the user's config6 file. It looks perfectly fine.

Can we see a list of all the files in the same dir as config6?

Are you aware of anything non-standard about the installation or your machine?

Hi, I think the link that you

Hi, I think the link that you created in your reply points to a jpg image, and not the config6 file, but anyway, I see that you received it.

Here is a screenshot of all the files in the bin folder:

I am not aware of any non-standard configuration on my PC; it is just a normal Windows7 PC for all I know, and I don't tamper with it. I installed GraphViz straight from the website (I think, like 4 times already now, because first, I had had one issue with an error message "GraphViz's executables not found", which I posted in a Python forum, and apparently the first time, not all files were installed for some reason, which already took quite some time to find out. Ever since the second time I installed it [after de-installing properly, from the control panel], that "GraphViz's executables not found" is not the problem anymore, but this error now ...)

Fixed. Thanks. Sorry to

Fixed. Thanks.

Sorry to trouble you again, but could you produce a list with file names and file sizes.

You installed the Graphviz .msi file from It is troubling that not all the files were installed. How did you know this?

Oh, you are not troubling me

Oh, you are not troubling me the slightest bit; I really wish to get the issue resolved, so I thank you indeed for yor time + patience :)

Okay, here is the content of the folder with file details, I hope that is the information you are referring to, and am always happy to provide more (3 images):

I install GraphViz from here:

When I had that first error (GraphViz's executables not found) in my IPython notebook, I (besides posting the problem in a Python forum) contacted the local Python MeetUp group and asked for help. One of them was kind enough to access my computer together with me via TeamViewer, and he went from the error message in Python to the module where the error message is programmed, and he guessed that some files must be missing. We looked in the directory, and could see way less files than what you see now. I de-installed and installed again, and that older error didn't come up anymore, but in lieu thereof, this one now ...


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