Late Thursday, a Santa Clara County (Calif.) Superior Court issued a preliminary injunction stopping Microsoft from setting up filters in its Outlook Express mail program that treated greeting cards from Blue Mountain as junk mail.

The companies' battle began in December when Blue Mountain sued Microsoft, alleging filters in a beta version of Outlook Express 5.0 were stopping its cards from reaching Outlook Express users. The company charged Microsoft took the action to stop anyone from competing with a similar service Microsoft recently put on its MSN portal.

Thursday's ruling extends a temporary restraining order issued in December until a decision is reached in the case. The judge also required Microsoft to alter its filtering so Blue Mountain cards are not placed in a separate folder.

Microsoft was given 30 days to comply. Company spokesman Tom Pilla said the company was reviewing the decision and would decide soon whether it would appeal.