Have also found (by trial and error) that the rule will not save if the Rule Name has any spaces in it. Bit wierd but it works.
Am now editing all my old rule names that used to work with spaces in, just in case. Strangely I found upon discovering the email rules in settings (had forgotten about them) they were de-activated. Am wondering if re-activating will ruin the current spam filtering which I've found increasingly effective, until recently.
