Editing David Ellefson (section)

===Feud with Mustaine===
Mustaine intended to release a solo album in 2004, which would become ''[[The System Has Failed]]'', although due to contractual obligations, Mustaine released it under the Megadeth name.<ref name=MegadethIsMe>{{cite web|title=Dave Mustaine: 'Anyone Who Says That Megadeth Isn't Me Is A Fool'|url=http://www.blabbermouth.net/news/dave-mustaine-anyone-who-says-that-megadeth-isn-t-me-is-a-fool/|website=Blabbermouth.net|date=March 31, 2007|access-date=October 6, 2012}}</ref> Ellefson and Mustaine had a severe legal disagreement over royalties and rights to Megadeth's name and back catalog, resulting in Ellefson filing an unsuccessful lawsuit. Though the two once enjoyed a close friendship, considerable animosity developed between Ellefson and Mustaine during this period to the point that on Ellefson's website, Megadeth was not mentioned in his biography, only in the discography.

In a mid-2005 podcast, Ellefson did not mention his past with Megadeth at all, instead concentrating on discussing his current projects. Mustaine felt Ellefson was unfairly using the Megadeth name when advertising an amplifier for [[Peavey Electronics|Peavey]]. Mustaine claims to have had dinner with Ellefson around Christmas in 2005 to talk things through; this got them on good terms, as Mustaine has stated that they spoke on the phone numerous times afterward.<ref>{{cite web|url=http://www.blabbermouth.net/news/megadeth-s-dave-mustaine-i-am-over-the-feuds-with-metallica-and-david-ellefson/|title=Megadeth's Dave Mustaine: 'I Am Over The Feuds With Metallica And David Ellefson'|publisher=Roadrunnerrecords.com|date=February 4, 2006|access-date=August 7, 2011}}</ref> In 2010 Mustaine and Ellefson agreed to keep any unresolved issues in the past and were working on building and maintaining their friendship again.{{Wikisource|David Ellefson v Megadeth}} Since this time Ellefson has gone on to say that he feels "that having that time away created a realization for both of us that, while we are both productive individually, Megadeth is definitely stronger with both of us in it together."<ref>{{cite web |title=Interview With Dave Ellefson, Founding Member of Megadeth |url=https://casinoreviews.com/blog/casinoreviews-interviews-dave-ellefson-founding-member-of-megadeth |archive-url=https://web.archive.org/web/20240129150826/https://casinoreviews.com/blog/casinoreviews-interviews-dave-ellefson-founding-member-of-megadeth |url-status=usurped |archive-date=January 29, 2024 |access-date=January 30, 2024 |work=CasinoReviews}}</ref>

Ellefson's dismissal from Megadeth in 2021 spurred renewed tensions with Mustaine, with the pair frequently attacking each other in interviews. Ellefson accused Mustaine of “not having his back” when the sexual misconduct allegations against him surfaced, while Mustaine has downplayed Ellefson's contributions to Megadeth and denied he was a founding member of the band.<ref>{{cite web |title=Yes, Dave Mustaine and David Ellefson are still talking smack about each other |url=https://www.loudersound.com/news/yes-dave-mustaine-and-david-ellefson-are-still-talking-smack-about-each-other |website=Metal Hammer |date=October 10, 2022 |access-date=March 13, 2023}}</ref>