diff --git a/core/views/survex.py b/core/views/survex.py
index e9593ae..2a38ad7 100644
--- a/core/views/survex.py
+++ b/core/views/survex.py
@@ -239,6 +239,9 @@ class SvxForm(forms.Form):
             # this is a new survex file being created from the template
             if not fname.parent.is_dir():
                 fname.parent.mkdir(parents=True, exist_ok=True)
+            if " " in self.data["filename"]:
+                errmsg =  "Error: Spaces are not possible in filenames.\n\nRename the file."
+                return errmsg
             if re.search(r"\[|\]", rcode):
                 errmsg =  "Error: remove all []s from the text.\nEverything inside [] are only template guidance.\n\n"
                 errmsg += "All [] must be edited out and replaced with real data before you can save this file.\n"