My GIMP worked fine until today. Today I started GIMP, and there are rectangular characters similar to this posting. I've reinstalled GIMP. After re-installation GIMP crashes and still rectangular characters.
I ran from the terminal, and this is what I got
<$ gimp
Fontconfig warning: FcPattern object weight does not accept value [50 200)
/snap/gimp/372/usr/bin/gimp: Gimp-Text-CRITICAL: gimp_font_factory_load_names: assertion 'fontset' failed
(gimp:8545): GdkPixbuf-CRITICAL **: 13:09:42.293: gdk_pixbuf_scale_simple: assertion 'dest_width > 0' failed
(gimp:8545): GdkPixbuf-CRITICAL **: 13:09:42.293: gdk_pixbuf_get_width: assertion 'GDK_IS_PIXBUF (pixbuf)' failed
(gimp:8545): GdkPixbuf-CRITICAL **: 13:09:42.293: gdk_pixbuf_get_height: assertion 'GDK_IS_PIXBUF (pixbuf)' failed
(gimp:8545): GdkPixbuf-CRITICAL **: 13:09:42.293: gdk_pixbuf_get_width: assertion 'GDK_IS_PIXBUF (pixbuf)' failed
(gimp:8545): GdkPixbuf-CRITICAL **: 13:09:42.293: gdk_pixbuf_get_height: assertion 'GDK_IS_PIXBUF (pixbuf)' failed
(gimp:8545): GdkPixbuf-CRITICAL **: 13:09:42.293: gdk_pixbuf_get_pixels_with_length: assertion 'GDK_IS_PIXBUF (pixbuf)' failed
(gimp:8545): GdkPixbuf-CRITICAL **: 13:09:42.294: gdk_pixbuf_get_rowstride: assertion 'GDK_IS_PIXBUF (pixbuf)' failed
(gimp:8545): GdkPixbuf-CRITICAL **: 13:09:42.294: gdk_pixbuf_get_n_channels: assertion 'GDK_IS_PIXBUF (pixbuf)' failed
(gimp:8545): GLib-ERROR **: 13:09:42.294: ../../../../glib/gmem.c:333: overflow allocating 18446744073709551615*18446744073709551615 bytes
(script-fu:8627): LibGimpBase-WARNING **: 13:09:42.856: script-fu: gimp_wire_read(): error
Trace/breakpoint trap (core dumped)>
Thank you for your suggestions.