Microsoft Teams Mac OS client is not recognizing external cameras after updating to version 1.3.00.18164.

Ok, so it looks like Microsoft basically turned off a feature that didn't need to be turned off in relation to Core Media DAL plugins. Please read more.

https://developer.apple.com/forums/thread/656944

 Essentially, they removed "disable-library-validation", much like Zoom did a couple of months prior. However, Zoom listened to their customers and re-enabled it until they have a better solution. So, basically, MS is not listening to their customers for....some reason?

Seriously, we should be mad here. This isn't something that MS had to do now. The fact that it is crickets from the team, or the fact that we have to disable codesigning ourselves on our own machines is crazy.

I had the exact same thing happen to me after updating to the latest version of teams.  However, I was able to come up with a solution that resolves the issue entirely.  It has to do with how Apple is starting to codesign specific apps to block 3rd party CoreMediaIO plugins.  If we remove that codesigning, then it will allow those 3rd party plugins to function again.

The fix is pretty simple.  First, completely exit out of Teams, then open Terminal and issue the following commands:

If you havent installed xcode previously, first run:

xcode-select --install

Then, run:

sudo codesign --remove-signature "/Applications/Microsoft Teams.app"

and:

sudo codesign --remove-signature "/Applications/Microsoft Teams.app/Contents/Frameworks/Microsoft Teams Helper.app"

Once you've issued those commands, open up Teams.  It should ask you for an administrator password to allow the (now) unsigned application to access your keychain.  Once entering your password and selecting, "Always Allow", the issue should be resolved. (At least until the next update to teams is released).

*****UPDATE*****

As of version 1.3.00.28778 the process has changed and the above workaround is no longer valid.  In order to get this fix working on the latest version of Teams, additional commands will need to be entered.  Keep in mind, these commands are relative to where you have Teams installed, so if it is in a different location, you'll need to adjust the file path accordingly.  So as it stands currently here are all of the commands (must be entered one by one and not pasted in one big block) that will need to be entered:

xcode-select --install (only if you haven't already)

sudo codesign --remove-signature "/Applications/Microsoft Teams.app"

sudo codesign --remove-signature "/Applications/Microsoft Teams.app/Contents/Frameworks/Microsoft Teams Helper.app"

sudo codesign --remove-signature "/Applications/Microsoft Teams.app/Contents/Frameworks/Microsoft Teams Helper (GPU).app"

sudo codesign --remove-signature "/Applications/Microsoft Teams.app/Contents/Frameworks/Microsoft Teams Helper (Plugin).app"

sudo codesign --remove-signature "/Applications/Microsoft Teams.app/Contents/Frameworks/Microsoft Teams Helper (Renderer).app"

Dear greghiggins3, Thank you for help and for posting this information on this community. I have unsuccessfully spent countless hours trying to make Teams and my Hero8 talk to each other. Your solution is the only one that has solve the problem. Thank. you. so. much!

Hi Grace,

The steps you've mentioned 'switching cameras and updated Catalina' did not resolve the issue. I'm on the latest OS and the only thing that works is like what was mentioned before to go back to a previous version of Teams which only works for about 24hrs and then it auto-updates and you have to re-install the previous version again....etc repeat.

Hopefully you can get a fix to this soon please.

thanks.

Hi Víctor JonathanLara Sánchez,

Thanks for posting in the forum.

Regarding your issue, please try to sign out Teams then restart Mac, re-sign in Teams to see whether the problem still occurs.

Also, try to plug out then plug in external camera in Teams app after restart Mac to see if there are any difference.

Moreover, you may try to uninstall and then reinstall to check this issue. See Uninstall Microsoft Teams.

If you have any updates on your side, please post back to us at your convenience.

Regards,

Grace