Big Sur on Macbook Pro M1 does not allow to add an Administrator account to a file

So, I'm trying to install MPlayer X on my new M1 Macbook Pro (http://mplayerx.org/download.html), and I get the now classic "You don't have permissions to open this file" or the like.

Previously I had some issue with another file , I opened the 'Get Info' Window, unlocked permissions and added the Administrator user besides my own user already added, and was able to run the file.

Now, I'm trying to do the same with the MPlayerX app to no avail. I already tried unsuccessfully the sudo upx -d path_to_app and the xattr -d -r com. apple. quarantine. I also tried chmod 777 etc, nothing.

Everytime that I tried to change the permissions for the users staff or everyone, from Read only to Read & Write, I get the 'The operation can’t be completed because you don’t have the necessary permission'

So it looks that even though that my own default account is an admin account, it doesn't have full permissions, it's not a real admin.

What could be a workaround of this? I tried booting, entering in recovery mode and creating a new Admin account, but it was not possible (using rm /var/db/.applesetupdone)

Other ideas?

Solution 1:

I actually had the same problem for some of my downloaded apps outside of the appstore .

Try this :

1. Press command + space and type terminal and press enter to open terminal

2. Paste this code in terminal and press enter .

sudo chmod -R 755 /path/to/app

Note : to get the path to app simply drag the file you can't open because of permission issues to terminal .

sudo xattr -dr com.apple.quarantine /path/to/app

3. Next paste this code with the path of the app and press enter .

You can open the file now with no permission problems .