(Reuters) - The FBI's upgrade of its computerized case file system has hit another snag and will not be fully deployed until mid-2012 after it crashed twice during a trial run by agents in October, according to a government report released on Friday.

The agency has struggled to upgrade its systems for years despite efforts by FBI Director Robert Mueller to make it a priority after the September 11, 2001, attacks.

The $451 million project, known as Sentinel, has experienced cost overruns and was temporarily halted a year ago when more problems emerged. Lockheed was originally contracted for the project but its role has since been significantly reduced.

The latest attempt to launch Sentinel hit a bump in October when a test by almost 750 agents led to it to crash twice, according to a report by the inspector general for the Justice Department, which oversees the FBI.

The FBI determined that the outages were a result of inadequate hardware infrastructure. As a result, completing Sentinel's development would be delayed until February and deployment would be moved back from January to May 2012.

The agency said that some 11,000 people within the FBI have already been using the system and that they are pleased with the progress despite the glitches.

We intend to deliver Sentinel right and under budget, the FBI said in a statement.