Valve Software will no longer build Steam updates or support customers who have Windows XP Service Pack 1, the company has announced.
The company will cease support for the operating system from August 31st. Steam users with Windows XP Service Pack 2 and above will not be affected.
In a statement to CVG, Valve has recommended that customers affected should run a service pack update.
"Our data shows less than 1 per cent of those on Steam are running XP Service Pack 1", the company added.
In January Valve said that Steam had accumulated more than 40 million active customers.
A Microsoft help page on upgrading service packs can be found here.