Metallica Newsted's departure, St. Anger:

As plans were being made to go into the recording studio in 2001, Newsted left the band,due to as he put it, "the physical damage I have done to myself over the years while playing the music that I love." However, subsequent interviews with Newsted and the remaining members revealed that Newsted's desire to release a CD and tour with his Echobrain side project - and Hetfield's intense resistance to such an idea - was the primary cause of Newsted's departure. Additionally, a Playboy interview revealed that the "hazing" that Newsted received since joining the band had not lessened over time. Finally, Newsted had never shared the songwriting partner status that Burton had enjoyed (in 15 years with the group, Newsted only co-wrote credit on three songs: "Blackened" from ...And Justice For All,"My Friend of Misery" from Metallica and "Where The Wild Things Are" from Re-Load).The 2004 documentary, Some Kind of Monster provided more insight into the reasons for Newsted's departure. In the film he says he felt his former bandmates decision to hire a therapist to help solve their problems was "really fucking lame. And weak."

In July, 2001, Hetfield entered rehab due to "alcoholism and other addictions". For nearly a year, Metallica ceased to function in any meaningful way. Ulrich and Hammett, for the first time, seriously considered the possibility that Metallica might be finished. Hetfield eventually returned to the band following his rehab hiatus and was required to work only four hours a day and spend the rest of his time with his family. Metallica continued slowly as a three-piece throughout the writing and recording of their next album. Longtime producer Bob Rock handled bass duties for the sessions. The making of the album was documented for the movie, "Some Kind of Monster". The film also exposed to fans that Metallica had sought the guidance of a therapist, Phil Towle, to deal with a vast amount of the band's inner turmoil.

Following the album's recording, Metallica held auditions for Newsted's permanent replacement in early 2003. Robert Trujillo formerly of Suicidal Tendencies, and Ozzy Osbourne's band, was chosen as the new bassist. Robert's resume also included Infectious Grooves as well as a stint with Black Label Society on their Boozed, Broozed, and Broken-Boned DVD. As Metallica moved on, Jason Newsted also found a new musical home joining Canadian thrash metal legends Voivod in 2002. In an interesting turn of events, Jason also became Robert's replacement in Ozzy's band during the 2003 Ozzfest tour (which included Voivod as part of the touring bill).

In June 2003, Metallica's eighth full-length recording, St. Anger, debuted at number one on the album charts. Being an intentionally raw and unpolished album, harsh criticism from fans followed. The record's under-produced sound, Hetfield's "flexible" sense of pitch, Ulrich's steely sounding snare, and the absence of any guitar solos received particular criticism. Despite this, the album won the best metal performance at the 2004 Grammys.

Having toured extensively for two years in support of St. Anger on the Summer Sanitarium Tour 2003 in festivals featuring Mudvayne, Deftones, Linkin Park, and Limp Bizkit and then the lengthy Madly in Anger with the World tour with Godsmack (in which nearly every performance was professionally recorded and sold on Metallica took a break from performing and spent most of 2005 with friends and family, however for two historic shows on November 13, 2005 and November 15, 2005, the band opened for the Rolling Stones at AT&T park in San Francisco.