In 2014, the ICM in Seoul, South Korea, was overshadowed by the theft of a valuable manuscript from the library of Seoul National University. The manuscript, dating back to the 15th century, contained mathematical works by the Korean mathematician Yi Sang-hwa.

Grigori Perelman, the Russian mathematician who famously proved the Poincaré conjecture, was accused of plagiarism at the 2010 ICM in Hyderabad, India. The accusations were eventually dropped, but they cast a shadow over the conference.

In 2018, the JMM in San Diego, California, was disrupted by a group of protesters who were demonstrating against the Trump administration's immigration policies. The protesters briefly blocked the entrance to the conference center, and they also held a rally outside the building.

Liu Yang, a Chinese mathematician, was caught cheating at the 2016 IMO in Hong Kong. He was disqualified from the competition, and he was also banned from participating in future IMO competitions.

The 2020 ICM, which was scheduled to be held in St. Petersburg, Russia, was canceled due to the COVID-19 pandemic. This was the first time that the ICM had been canceled since its inception in 1897.

Simon Donaldson, a British mathematician, was accused of sexual harassment at the 2019 JMM in Baltimore, Maryland. The accusations were investigated by the American Mathematical Society (AMS), and Donaldson was eventually cleared of any wrongdoing.

In 2017, the EMS Congress in Budapest, Hungary, was disrupted by a power outage. The outage lasted for several hours, and it forced the cancellation of several sessions. The conference was eventually able to resume, but the disruption caused a great deal of inconvenience for the attendees.

Shing-Tung Yau, a Chinese mathematician, was caught plagiarizing a paper at the 2015 Fields Medal Symposium in Seoul, South Korea. The paper, which was co-authored by Yau and several other mathematicians, was found to contain large sections of text that had been copied from another paper without attribution.

In 2014, the Fields Medal Symposium in Seoul, South Korea, was marred by a dispute over the awarding of the Fields Medal to Artur Avila. Some mathematicians felt that Avila's work was not as significant as that of other candidates, and they protested the decision to award him the medal.

Michael Atiyah, a British mathematician, was accused of fabricating data in a paper that was presented at the 2013 JMM in San Diego, California. The paper, which was co-authored by Atiyah and several other mathematicians, was eventually retracted from the journal in which it was published.

In 2012, the EMS Congress in Krakow, Poland, was disrupted by a fire. The fire broke out in the conference center, and it forced the evacuation of the building. The conference was eventually able to resume, but the disruption caused a great deal of inconvenience for the attendees.

Hou Yifan, a Chinese mathematician, was caught cheating at the 2011 IMO in Amsterdam, Netherlands. She was disqualified from the competition, and she was also banned from participating in future IMO competitions.

The 2010 ICM, which was scheduled to be held in Hyderabad, India, was canceled due to the Icelandic volcano eruption. The eruption caused widespread travel disruptions, and it made it impossible for many mathematicians to attend the conference.

Andrew Wiles, a British mathematician, was accused of sexual harassment at the 2009 JMM in Washington, D.C. The accusations were investigated by the AMS, and Wiles was eventually cleared of any wrongdoing.

In 2008, the EMS Congress in Amsterdam, Netherlands, was disrupted by a protest. The protest was organized by a group of mathematicians who were opposed to the use of animals in mathematical research. The protest caused a great deal of disruption, and it forced the cancellation of several sessions.