Bill Gates has revealed his dissatisfaction at Microsoft's pace of innovation over the past few years, heavily criticising it's early mobile strategy.
Speaking during a news conference at a new research facility in Mexico City, Gates was unequivocal about Microsoft's approach to the mobile market, lamenting missed opportunities to gain a market share.
"We didn't miss cellphones, but the way that we went about it didn't allow us to get the leadership. It's clearly a mistake," Gates told CBS.
After falling behind to industry leaders such as Samsung and Apple, Gates unsurprisingly remained coy on the position of CEO Steve Ballmer, praising his performance but insisting more can be achieved.
"(Ballmer) and I are two of the most self-critical people I know," Gates said.
"There are a lot of amazing things that Steve's leadership achieved — Windows 8, the Surface computer, Bing, Xbox. Is it enough? No.
"He and I are not satisfied that in terms of breakthrough things we are doing everything possible."
Criticism is becoming a familiar constant for Ballmer, appointed to the role in February 2000, with Microsoft shares plunging 45% over the last decade.
Top of Ballmer's critics include former senior Microsoft executive Joachim Kempin, who accused Ballmer of forcing out any rival manager within the company - to safeguard his position at the top.
The claims, published in Kempin's book about his time at the company, were a heavy blow to Ballmer at the time, but his close relationship with Gates seems to be keeping his head above water - at least for the time being.
And while Microsoft's sluggish adoption of mobile has cost the company in the long-term, Gates can take some solace in the company being named CIOs preferred "mega-vendor", in a report published last week.
Whether that is enough to save the battling Ballmer however, remains to be seen.
Did Microsoft miss the mobile boat so to speak? Is Steve Ballmer the man responsible for this? Tell us your thoughts below