Image Writer cannot write to network drives


my Image Writer node cannot write to network drives. What am I doing wrong?

ERROR Image Writer         2:21       Execute failed: Output directory 'B:\' is not writable

I have tried diffent drive letters, same problem. My system is Windows 7 Professional SP-1 (64-Bit), needless to say, that I have all admin rights on this machine.


Hi Marc,

I guess we know that problem. It's related to a problem in the underlying library we use (SCIFIO). We will make sure to have it fixed asap.



Hi @christian.dietz, any update on this one?

The Image Writer node apparently still cannot write to mapped network locations.

The same problem here.

Have you tried the new Image Writer (Port) (Labs) in KNIME Labs? It has an optional, dynamic file system input port that you can select.

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Yes. The new Image Writer (Port) (Labs) works. Thank you.


The original issue was about the Image Writer node (the one that takes Img column type as input), not the Image Writer (Port) node.

Nevertheless, I can confirm that with:

KNIME Analytics Platform	4.2.2.v202009251451
KNIME Image Processing

… also the Image Writer node works fine on mounted network drives (i.e. both using a drive letter, e.g. W:\ as well as using a raw network mount, e.g. \\fileserver\some\path).



sorry, i have the same problem with the image Writer (port).
cannot write a Image to a network folder.

Or I didn’t understand the role of the image writer. :thinking:

A part of my workflow:
Image Writer

Image Writer (Port)-2-network adress

Thx in advance


Looking at your workflow the pie donut chart does not create/fill the output port, therefore the red cross at the output port. Open the nodes dialog and adapt the according option and everything should work as expected.



Hello mark_Ortmann,

which dialogue do you mean and where do I open it?


Click on Generate image, sry that I did not mention the name of the option in my previous response.

Thx ! It works :+1:, but in what format is the image written?
Where can i set it (*.png or *.svg)?

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When you hover over the output port of the pie chart node it says the image is a svg, therefore I’d use the appropriate file extension when writing the file. Note that the image will be an svg even if you name your file image.csv

Anyways you’ve made a good point here - it should be easier for you to write the proper format. I’ve opened a ticket for this.



Hi again,

thank you.

Pie Chart SVG Image Outport




Dear all,

I am having the image writer node not writing onto an external location problem at the moment. The workflow reads the files from a server location and processes them. The last processing node outputs a table with the final processed images and their respective file names. The Image Writer node writes just fine onto the local drive. However, on attempting to write onto the server (either using the drive letter or raw network mount), I get an error: “Output directory xxxx is not writable”.

During configuration of the node the network share is found and the path is correct, the light on the node is yellow following configuration but then throws an error as it is being executed.

We are an imaging facility and users should save their data on the server and not the local image analysis machines.

Is there anything I can try?



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