Family history online giant Ancestry was down for several hours on Friday morning (10 August), across all its global sites.
UPDATED: The problem was eventually resolved around 10am BST.
The Ancestry website was out of service from at least 6am BST when Ancestry.com announced on Twitter: "We are aware of the site outages right now. We apologise for any inconvenience and working to resolve the issue. We'll let you know as soon as everything is back online."
On the Ancestry site there was a message stating: "We are undergoing maintenance or resolving some errors. We apologise for the inconvenience and ask for your patience at this time."
The company's subsidiary Rootsweb.com website was unaffected.
Most Ancestry.com users have been patient with the family history site but there were some who complained that this was not an isolated outage problem.
"This is a common occurrence for me every night. It just seems to be happening a little earlier than usual! I have been complaining to Ancestry for several months now. This happens every night/morning. Most people aren't researching during these hours so many probably don't notice it" moaned one Ancestry user on the site's Facebook page.
Other users denied this.
Ancestry is the largest online provider of genealogical data, with two million paying subscribers, and operating a network of historical record websites focused on ten countries including the US, Ancestry UK, Australia, Canada, and China.
The company also develops genealogical software, such as Family Tree Maker, reviewed.
As of June 2012 the company provided access to more than 10 billion records and 38 million family trees.