From Ace of Spades:
After The New York Times publication, the FBI Washington Field Office began investigating Clinton’s use of private emails and whether she was using her personal email account to transmit classified information.
According to sources, McCabe was overseas when he became aware of the investigation and sent electronic communications voicing his displeasure with the agents.
"McCabe tried to steer people off the private email investigation and that appears to be obstruction and should be investigated," said one former FBI official with knowledge of the circumstances surrounding the investigation.
"Now if the information on the 'stand-down' order is obtained by the IG that could bring a whole lot of other troubles to McCabe."