AOL warned that a mess up which left an unknown number of users blocked from its IM service could take until Monday to fix.

The company regularly engages in a routine task of opening unused screen names to new users, but whilst recently doing so it mistakenly deactivated a number of currently active AOL Instant Messenger accounts, locking those users out of the system in the process. They are still working on a fix. AOL would not say how many accounts had been affected by this.

"This week, we released a group of AIM screen names which was overwhelmingly comprised of just such abandoned screen names. Unfortunately, however, a small number of active screen names were also inadvertently included." - AOL spokeswoman Krista Thomas.