Hi,
they posted a possible solution to this error in the US forum and there was also a possible solution posted in a german speaking thread in the eu forum.
You can try this solutions and hopefully they will work as they worked for me.
Here the link to the US forum:
https://us.forums.blizzard.com/en/wow/t/mac-users-have-to-learn-code/1132967/6
If you are familiar with the command line try this command:
sudo chmod -R 777 /Applications/World\ of\ Warcraft/Data
Best luck.
I’m also a Mac user affected by this issue. The problem with all the workarounds/solutions posted by users in the US thread is that none of them are permanent. If I reboot my Mac or quit and restart the Battle.net app then I’m back to square one.
Fortunately I can play WoW by bypassing Battle.net and running the WoW apps directly.
It seems you’ve missed my mention on chmod. It does not work. I already checked the permissions for the complete directory, the shared agent and moved the application to my users folder to try circumvent any administrator privilege f*ck ups from the battle.net client but to no avail.
Oh sorry, you’re right.
I was so happy that this solution worked for me, that I overread the chmod part of your post…
Seems this fix doesnt work for everyone…
Have you tried running the WoW apps directly? It seems that the updater reverts these chmod changes…
Yes, I can. Thats a workaround for now until a patch is necessary to play. I hope Blizz will fix the battle.net client until then.
I’m running WoW via Wine and had the same problem on Ubuntu. Tried various proposed solutions on the US forums, including sudo chmod, with no success. Then I tried the one with the addons and it worked… temporarily! My method is:
Not sure if it works for Macs but you should definitely try it if the other methods didn’t work for you.
Somebody has posted a fix which appears to be permanent on the US Blizzard Mac forum. In my case, the file was completely different but deleting it worked:
https://us.forums.blizzard.com/en/wow/t/wow-wont-update/1132237/350
If you are happy using CLI commands (i.e. the Terminal app) then this will quickly find the file causing the problems:
Make sure you quit the Battle.net app first.
cd /Users/Shared/Battle.net/Agent/Agent.7581/Logs
grep -i agentasadmin *
You will see a (probably long) list of error messages saying “AgentAsAdmin failed to fix the file permissions of ‘Some file name’”.
Delete that file with:
rm ‘Some file name’
e.g. rm ‘/Applications/World of Warcraft/classic/D:/_work/gfx_cvars.csv’
(that was the file in my case - will probably be different for you).
After deleting the file I started the Battle.net app and all was OK. It didn’t ask for an admin password and started updating all my games as usual.
I’ve confirmed that rebooting my Mac doesn’t break this fix - still working nicely for me.
The fix posted on the US forums works.
Here it is for convenience:
This may just be me, but I’ve found if I just ignore battle.net and instead go directly to the wow folder and navigate to the application itself then it will open as normal. Requires you to manually enter your login and authenticator details but no other problems. Playing classic generally so dunno if retail also opens that way without issue.
This has to be repeated every time you quit the Battle.net app or reboot your Mac. My post above has an easier and more permanent solution.
Yes I noticed this.
Mine was the gfx windows file in Classic as a culprit, for others it’s the game controller file in their PTR folder.
Delete the rogue file and problem goes away but the mind still boggles why Blizzard hasn’t applied a fix for this themselves as of yet.
This worked for me too, thanks for posting this, it was also the same file causing my issue.
Tried everything excluding sudo and nothing worked. However, starting and then immediately stopping all updates in the Download arrow worked perfectly. Now I have 3 paused updates and see the button Play and can enter the game.
Same Battle.net client problem as OP, mac OS Mojave 10.14.6.
edit: the sudo chmod -R 777 /Applications/World\ of\ Warcraft/Data trick worked for me, at least temporarily
I still cannot launch the game 
Edit:
I have even uninstalled and reinstalled the game, but STILL this happens. Also tried to locate different files etc that have previously been suggested, but with no success… Please Blizz or anyone, help!
The chmod fix worked for me, but it does not seem to work for everyone.
In the meantime, you can launch the application directly and bypass the Battle.net app. In the absence of a fix this will work until the game needs updating.
Having the same problem on my mac.
Weirdly it was gubbed last Wednesday/Thursday but on Friday through the weekend it worked fine WITHOUT me doing anything to any files. But again today Battlenet keeps giving me an error message.
TBH I dont see why I should be messing about with files when the problem lies with Blizz, they need to get their finger out and sort it.
Thanks, worked for me as well, though in my case it were symlinks I created quite some time ago.
Exactly. I’ve seen a lot of people discussing “fixes” which mean people need to mess about with files they don’t understand when it’s not necessary because this issue is on blizzards end, and blizzard need put out a fix.
They used to be really good at fixing things like this promptly but it’s been over a week now with no fix or updates from them 
That was very useful. Thanks, it solved the issue for me.