Ferguson was furious with Ferdinand on Saturday when the 33-year-old defied his order to wear a T-shirt backing the Kick It Out anti-racism campaign.
But yesterday he revealed: "I spoke to Rio.
"The issue is pretty simple. There was a communication problem.
"He felt I should have spoken to him on Friday and I didn't anticipate there would be any problem in the dressing room as far as the T-shirt was concerned.
"I have listened to the conviction of Rio and I think it is quite compelling. I can understand his stance.
"But I think you are always stronger as a union. There's more solidarity than as a single unit.
"The advice I would give is that he should take it up with the proper authorities. It is only through that he will make his voice heard.
"Obviously as the manager of the club when you lay down policy you don't want to see it being ignored. That's where my anger came on Saturday.
"But we have resolved the situation, there are no lingering problems and we move on. That is the end of the matter."