Ole Gunnar Solskjaer says Manchester United supporters need to be listened to, but has called for any future protests to be "civilised".
Sunday's demonstration against the club's owners forced their Premier League match with Liverpool to be called off after fans broke into Old Trafford.
The United manager admits "it's everyone's right to protest" but said when police are injured they are "scarred for life".
"It was a difficult day for us. Of course we wanted to play, we wanted to beat Liverpool for the fans because our job has to be on getting good performances and good results on the pitch.
"As I said before the game, we have to listen. We have to hear the fans' voice. It's everyone's right to protest. It has to be in a civilised manner though.
"Unfortunately, when you break in and when police officers get injured, scarred for life, that's too far.
"When it gets out of hand like this, it's a police matter. It's not about showing your opinions anymore."
The United boss is hopeful that communication can improve between their owners and fans but he says division will hurt everyone.
"It has to be a united football club. To make things grow, you need to give it some patience. I'm hopeful that in time we can unite and come together.
"Frictions and challenges, sometimes that's good and can move things forward. The last few weeks have been difficult.
"I've had backing. I'm responsible for results and football matters and I understand fans want to see results and trophies. We're hoping they can see this team is going place, moving forward.
"Hopefully we can get to a final tomorrow. That's the short-term fix and we'll have to take it from there."