I've been trying to use the Union tool on a layer of building polygons, with a layer of output area polygons. The building layer has the largest number of features I've used so far, 106716, if that's relevant.

Yesterday, QGIS was just freezing up trying to do the Union, and I ended up cancelling it with a view to giving it loads of time today.

However today I've been getting an error that reads:

No output created. File creation error: creation of layer failed (OGR error:Failed to open Shapefile `G:/New folder\Test.shp'.)

Can anyone help me resolve this new error?

  • Perhaps check if both layers do not have geometric errors? You can try running the Geometry Checker plugin or the Check validity tool from the Processing Toolbox. Have you also tried running the Union tool and saving the output as a temporary file instead?
    – Joseph
    Commented Aug 9, 2016 at 10:30
  • I checked both layers using Vectors->Geometry->Check Validity, and they both reported 0 errors. Trying to figure out how to specify a temporary file, to try the other thing you suggest. Commented Aug 9, 2016 at 10:57
  • Always good when there's 0 errors :). When you run the Union tool, just don't specify a path for the output.
    – Joseph
    Commented Aug 9, 2016 at 10:58
  • 1
    You can try the tool from the Processing Toolbox, there you do not need to specify a path. I'm guessing you were using it from Vector > Geoprocessing Tools > Union....
    – Joseph
    Commented Aug 9, 2016 at 11:07
  • 1
    Update! Everything's now going fine, this error was probably due to my USB getting all full up with QGIS junk. Thanks! Commented Aug 11, 2016 at 12:55

1 Answer 1


It turns out that this error was due to the memory stick I was using being full up, this meant it didn't have the memory to make any of the temporary files it might need to to run the Union tool.

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