Trump eventually arrived to meet the royal, part of his current visit to the United Kingdom, but Twitter users were already outraged that the 92-year-old had been made to stand in the 80 degree heat and wait.
Next, the President and Queen inspected the front rank of the Guard of Honour, while the first lady remained on the dais.
As the Trumps were meeting the queen, the indictment of 12 Russian military officers for hacking the Democratic National Committee was handed down by the USA attorney general.
Russians Indicted for DNC Hack, Stealing Voter Info
Trump's lawyer, Rudy Giuliani, said on Twitter that it was time to end the Mueller investigation since "no Americans are involved".
While inspecting the guard at Windsor, the Queen appeared to give direction to Mr Trump but then the president abruptly halted and she was forced to walk around him. "The feeling inside the palace is that Trump's disrespectful mistakes with the queen were bad and inexcusable".
US President Donald Trump urged Theresa May to be "brutal" and "tough" in Brexit negotiations, but she ignored his advice to "overshoot" her true targets.
The trade deal's fate, though, really hangs on the fragility and temperamental nature of Trump's mood and, if he looks out his hotel window at the mass protests and demonstrations happening in London, it might well be called off once again. According to CNN, the Trumps chatted with the queen after the inspection ceremony, listened to the military band play and watched the Coldstream Guards march in formation before heading into the castle for tea.
He said: "I think he has not been hospitable to a government that is very important. She is just an incredible woman", Trump told The Sun newspaper.
North Korea snubs USA , skips meeting on returning remains
Although Pompeo insisted progress continued to be made, North Korea accused the United States of making "gangster-like" demands. Some are pilots who were shot down, some are ground troops, others may be those who died in prisoner-of-war camps.
The Queen, who has entertained all manner of world leaders during her 66-year reign, was described as the "perfect host".
"You could see that suppressed dominance where he felt that he had to still motion to her".
"My mother loved the queen". Trump, who is known for his lengthy, powerful and intense handshakes, had many a little anxious about what would happen when he met the world's longest-serving monarch.
Elizabeth has now met every USA president since Dwight Eisenhower with the exception of Lyndon Johnson, who did not visit England while in office.
North Atlantic Treaty Organisation summit: EU's Tusk warns president to appreciate allies
Trudeau, who was called "weak" by Trump after the G7 meeting, pledged to boost Canadian troop numbers 540, from around 450 now . Asked for comments on Tusk's remarks, Trump said that the United States did "have a lot of allies".