[GIS] QGIS change geometry type in shapefile

Question

I have 7 shapefiles which I would like to combine using the 'Merge shapefiles' function in QGIS. I got the error message that the shapefiles must all be the same geometry. I checked this, one shapefile has the geometry 'WKB type – PolygonZ' – I think this was a shapefile created when I used the Vector-dissolve function. All the other files have the geometry 'Polygon'. How do I change the geometry of this shapefile – or is it a case of recreating and re-saving the original shapefile?

Answer 1

From @Joseph comment :

Right-click the layer and select Save As.... In the Layer Options section, there is a dropdown menu for SHPT. Select Polygon, this should re-save the polygon layer without the z-dimension.