Merging vectors 'global name 'dataobjects' is not defined'

Question

I'm trying to merge contour line shapefiles but I keep encountering errors when doing so. I'm using Vector > Data Management Tools > Merge and selecting all six line shapefiles and given the error 'global name 'dataobjects' is not defined'.

I have also installed the MMQGIS plugin to try an alternative but receive a python error as soon as I click MMQGIS > Combine > Merge Layers...

Traceback (most recent call last): File "C:/Users/me/.qgis2/python/plugins\mmqgis\mmqgis_menu.py", line 316, in merge dialog = mmqgis_merge_dialog(self.iface) File "C:/Users/me/.qgis2/python/plugins\mmqgis\mmqgis_dialogs.py", line 1714, in init mmqgis_load_combo_box_with_vector_layers(self.iface, self.sourcelayers, True) File "C:/Users/me/.qgis2/python/plugins\mmqgis\mmqgis_dialogs.py", line 2610, in mmqgis_load_combo_box_with_vector_layers combo_index = combo_box.findText(layer.name()) AttributeError: 'QListWidget' object has no attribute 'findText'

I've set the CRS to OSGB 1936 / British National Grid for all layers and the project CRS in the same.

The shapefiles are found here: https://www.dropbox.com/sh/w5zg5b8otfz2e3c/AADoACxzlBW789O3u2-8SgC9a?dl=0

Answer 1

This is a bug in QGIS 2.18.4. Update to 2.18.5.

Answer 2

I think there's something wrong with the prj files you have because although they mention "British_National_Grid", my QGIS just loads a user-generated CRS.

So you could try re-saving your layers (right-click your layer then go to Save As...) with the relevant CRS again.

Or you could use SAGA's Merge vector layers tool:

Processing Toolbox > SAGA > Vector general tools > Merge vector layers