I'm trying several spatial statistics analysis in my QGIS 2.18.3 project (convex hull, random points inside polygons, point sampling tool, basic statistics for numeric fields, distance matrix, nearest neighbour analysis, mean coordinates, polygon centroids).
Since I used the nearest neighbour analysis, which is saved under a .html in my data folder, I cannot save any other layer as a shapefile (shp). The proposed type of files are just .dbf, .xlsx, .csv and .ods. Encoding is set as System. Pre-selected type of file is .dbf.
Result is that mean coordinates and polygon centroids are not visualised in the project.
I tried to create a fix buffer that I already did this morning and even that layer was not able to be saved under a shapefile, but in the morning it was possible.