Vidic left United for Inter in 2014.
"The club was going through a lot of changes, in the same way as Manchester United were," Vidic recalled.
“There were big expectations for me and I tried hard, but there was trouble for me from the start. We played three at the back. I played in the middle and felt like I was there to fix problems, but even if there were no problems you'd get them in that position.
“I didn't enjoy that role – I hadn't played it for a long time. I tried to adapt but it just didn't happen.
“Then [Roberto] Mancini arrived. We didn't start well; I didn't play for two or three months. We didn't have a great relationship. Then I got injured. That's basically the story."