Can't start Omnisharp because of mono version

Question

Whenever I start up VS Code on my Mac (Yosemite), I get the following error in VS Code

Error: Cannot start Omnisharp because Mono version >=3.10.0 is required

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Answer 1

If you followed the instructions at the asp.net website, then you should already have brew installed. If you don't you can install it from this website: http://brew.sh

After you have that installed open a new Terminal and run the following:

brew update && brew install mono

Then you should be good to go. I just went through these same steps myself.

Answer 2

TLDR; brew update && brew unlink mono && brew install mono

---

Gathering those two answers was necessary to resolve this for me.

I did run the script suggested by @myke-bates from here

Which at the time of writing is:

#!/bin/sh -x

#This script removes Mono from an OS X System.  It must be run as root

rm -r /Library/Frameworks/Mono.framework

rm -r /Library/Receipts/MonoFramework-*

for dir in /usr/bin /usr/share/man/man1 /usr/share/man/man3 /usr/share/man/man5; do
   (cd ${dir};
    for i in `ls -al | grep /Library/Frameworks/Mono.framework/ | awk '{print $9}'`; do
      rm ${i}
    done);
done

The as suggested by @ky6yet I ran brew-update && brew install mono to be advised that I had to unlink mono first so in fact I had to run

brew update && brew unlink mono && brew install mono

At least in my case running the script to remove mono first wasn't necessary.