Google last week mistakenly disabled the Gmail accounts of some users due to an apparently overzealous attempt by the company to combat spammers.
On Wednesday night, people started reporting in the official Gmail Help Discussion forum that Google had locked them out of their accounts.
A Google staffer who patrols the forum and posts messages on behalf of the company acknowledged the existence of a problem on Thursday afternoon.
"I understand that some of you have had a frustrating experience with your accounts being inappropriately disabled. Our team is aware of the problem, and our engineers are continuing to investigate," this person, identified as Google Guide, wrote.
Google Guide later provided more details about the situation, saying that it was the result of an effort to purge users who abuse the service, such as spammers.
People whose accounts were disabled by mistake should have regained access to them already and no data should have been lost, the Google staffer wrote.
Google spokeswoman Courtney Hohne confirmed that Gmail would not accept messages sent to those accounts while they were disabled, returning a "bounce-back" notice to senders. Gmail will not automatically attempt to redeliver those rejected incoming messages, she said via email.
"Our goal has always been to keep Gmail free of people who abuse the service and to keep Gmail inboxes free of spam. We've been targeting a large network of spammers to keep them out of the Gmail system and accidentally disabled access to some other accounts," she wrote.
As recently as late Friday morning Eastern time some people were still complaining of being locked out of their accounts.
The discussion thread is at press time one of the longest in recent months, and is full of frantic pleas for help from affected people who use Gmail as their primary e-mail service for personal or work communications.
Hohne said the mistakenly disabled accounts affected "a small fraction," well below 1 per cent of the tens of millions of Gmail users.
In addition to the problem of disabled accounts, in the past month a steady stream of Gmail users have been complaining that when they get upgraded to the new version of the service, popularly called Gmail 2.0, the service becomes extremely slow, often fails to load pages and even crashes their browsers.
One of several threads devoted to this issue in the Gmail Help Discussion forum continues growing, nearing 300 messages at press time.
Gmail 2.0, which features an upgraded contacts manager and is designed to be faster and more stable, is based on what the company calls "a major structural code change."
Gmail isn't just a free web mail service for individuals, but also part of the company's Google Apps suite of hosted collaboration and communication applications suite, which is used by more than 100,000 organizations, mostly small businesses, as well as by hundreds of universities.
Google offers a service-level agreement of 99.9 per cent uptime to people and organizations that sign up for the Premier edition of Google Apps, which costs $50 per user per year.