Firefox fans held parties around the world to mark download day
Mozilla is claiming a download record for the release of Firefox 3.0.
In the first 24 hours the web browser was available the software was downloaded more than eight million times, says its creator Mozilla.
Statistics from the download servers are being scrutinised to produce an official figure that will be passed to the Guinness World Record organisation.
But the launch was marred by news from computer security firms who have found the first flaws in the software.
The attempt to set the download record was scheduled to begin at 1300 PST (2000 GMT) on 17 June.
However, the record attempt was almost wrecked from the start as the servers handling the downloads collapsed under the weight of visitors checking to see if new version was available.
Once the servers were up and functioning normally the record attempt began.
At their busiest the servers were handling more than 9,000 downloads per minute. Within five hours the number of downloads for Version 3.0 exceeded the 1.6 million set by Firefox 2.0 in October 2006.
In total Firefox 3.0 was downloaded 8.3 million times over the 24 hour record setting period. The figure beats the five million Mozilla predicted before the day.
Logs from the download servers have been handed to the Open Source Labs at Oregon State University for auditing. The scrutiny will ensure duplicate and unfinished downloads are not counted. The verification process could take a week to complete.
The surge of interest in Firefox 3.0 has continued and Mozilla has reported that the software has now been downloaded more than 10 million times.
However, some of the shine of the launch was removed by reports that a security firm had already found a flaw in the browser.
DV Labs/Tipping Point reported a flaw only five hours after Firefox 3.0 debuted. The flaw potentially lets an attacker take over a PC if a user clicks on a booby-trapped link.