A major upgrade to Gmail is getting the thumbs down from users who complain that the new version is extremely slow, often fails to load pages and even crashes their browsers.

People have flooded discussion forums with complaints since Google began "upgrading" users about two weeks ago to the new version, popularly referred to in the blogosphere as Gmail 2.0.

Ironically, Gmail 2.0, which features an upgraded contacts manager, is designed to be faster and more stable. Gmail 2.0 is based on what a Google spokesman calls "a major structural code change" upon which new features will be launched in coming months.

"Most users should see a marked improvement in performance. We recommend using IE7 and Firefox 2 to take full advantage of Gmail's speedier interface," said spokesman Jason Freidenfelds via e-mail.

Asked about the problems users are reporting, Freidenfelds didn't address the complaints specifically but said that Google appreciates the feedback it's getting. "The new code underlying Gmail should allow us to roll out performance improvements more frequently," he said.

Users interviewed via e-mail for this article report a variety of performance problems with Gmail 2.0.

The most common complaint is that it is generally very slow, with delays of a minute or more when attempting to display the inbox upon logging on, to record keystrokes when typing text and to respond to mouse clicks. Often the tasks time out. Others report that Gmail 2.0 repeatedly crashes or freezes their browsers, in particular Firefox.

If these users switch to the "old" Gmail version, the problems go away. However, these users say they have to switch manually every time they log on, because Gmail 2.0 automatically became their default version once they got upgraded to it.

When Google upgraded his account last week, Jim Sellers, a software programmer based in Ottawa, Canada, was eager to try Gmail 2.0's improved contacts manager, but his Firefox 2.0 browser kept crashing both on Windows 2000 and Mac OS X 10.4.

"These problems were very disruptive. I spend at least 25 percent of my day using my browser as one of my main working tools. To have it crash like that made the new version of Gmail a non-option," said Sellers, an otherwise satisfied Gmail user since June 2004.

The IDG News Service is a Network World affiliate.