The default VizieR target search radius was recently modified to 2arcmin
The default target radius was set to 10arcmin since the first version of VizieR (11 years ago!), at an epoch where only very few catalogues reached the million rows : with 1,000,000 rows over the full sky, the average density of sources is just 2 per circle of 10' radius. The recent surveys are very rich, and also astrometrically accurate, therefore this default radius was reduced to 2arcmin -- the same value as the Simbad default target radius. The average of 1 source in the new default target is reached for catalogues having around 12million rows.
If for any reason you would like to keep the previous default 10' target radius, use the url http://vizier.u-strasbg.fr/viz-bin/VizieR?-c.r=10