Switching to proton 8 fixed it for me, until the next time I launched the game. Then it was back to the same old problem. I tried a lot of things but what finally worked was reinstalling battle.net with system libraries disabled in global options and then switching to proton 8.
(I don’t redownload the game.I keep the game in a separate folder and just point battle.net to it. I’ve done many reinstalls.)
The confusing thing is that “Wine-GE-Proton8-26” also has GE-Proton in its name but is the wrong file from the wrong repository. Asaftiifm finally pointed me to GitHub - GloriousEggroll/proton-ge-custom: Compatibility tool for Steam Play based on Wine and additional components - another GE-Proton but now the right repo.
I had searched for “lutris update wine version” but could not find this link anywhere - probably because it was obvious to anybody but me. I’m putting my search words here just in case somebody else is having the same problem.
Same issue here -
tried changing runners etc, nothing seems to work,
when i change runner to the only proton option i have (ge-proton) battlenet doesnt even load up
My only other 2 options are * wine-ge-8.26-x86_64 (default ) and System 9 Ubuntu 9.0 0 repack 0 4+ zorin
Both bring up battlenet but eventually error out on update 
not sure if its possible to add more runners to an existing setup that may work ?
i used protonup-qp as well, tried most runners under various options, NONE of them worked
There is a certificate problem at blizzard, so updates are being affected.
For people with game update errors relating to BLZBNTAGT00000854 see the linked thread.
If you’ve got specific errors that doesn’t follow the above, then bring them to the fore, and we’ll see what we can do.
This thread is about BLZBNTAGT00000840 and I can confirm that switching wine versions works.
After Lutris update function downloaded the default ge-proton into ~/.local/share/lutris/runners/proton - go to (1) if your lutris does not update - using that version convinced battle.net to finish the download correctly. Thanks everybody for the help.
@evillone more runners can be manually placed into ~/.local/share/lutris/runners/proton or ~/.local/share/lutris/runners/wine.
don’t forget to install umu-launcher to use ge-proton and Steam proton in Lutris (not Flatpak).
I did not install umu-launcher (I wouldn’t even know from where) or Steam. It was not necessary (no flatpak). GE-Proton downloads some package from steam on first usage. That was enough.
Edit: Although proton-ge installed lots of system libraries that my system already has (why use system libs if you can double up? /sarcasm), there is nothing with the name umu-launcher. It is apparently not necessary to use proton-ge. I do not have Steam. Well, now I have, kind of …
or it is already installed for you, it is a necessary component for Lutris to use Steam Proton or proton-ge
@ kaimon
Thank you so much for the response and the tips,
Read through all those threads , added some more wine runners but did not work,
what DID work for me was the following , upon seeing this screenshot in the threads you shared
hope that helps some folks that were not having any luck with the above posted workarounds.
thanks again to all for contributing this was really helpful and a learning experience for me a , ‘Nix N00b’
Cheers !
UPDATE:
I installed linux fresh and have no battlenet client.
even with the Proton experimental 9 and hotfix I could not install battlenet with lutris
my code is BLZBNTAGT00000854.
any idea?
thanks restartet lutris then i saw it
This is probably part of a bigger problem that isn’t yet solved, as HotS also won’t install even after Battle.net started. Looking up the error codes in regards to wine shows that it’s a recent and common problem.
The appropriate fix to solve these issues are part of GEproton9-23 (see very first entry). I strongly suggest implementing this as custom runner for Battle.net in the installer.
I’m not sure why this took a couple of tries but updating the runner to GEproton9-23 did eventually work. (None of the other runner swaps recommended worked for me.)
This is not super relevant but just FYI if you stumble into this thread, the newer versions of wine staging didn’t appear to work. I tried the 10.0 version which came out yesterday (Jan 21st).
She’s baaacckk ! lol
in Lutris , switched runner to ‘Proton Experimental’ completed updates,
then switched back to default runner.
All is well 
I had to switch back from ‘Proton Experimental’ to ‘wine-ge-8-26-x86_64’ and then i could update and play again. Just in case for someone else the Proton environment doesn’t work.
Hi. I had the same issue.
Ubuntu 24.10
Latest Lutris.
Also reinstalled diablo 4. But no change.
Then I installed with ProtonUp-Qt (ProtonUp-Qt-2.10.2-x86_64) wine-proton-9-0-4-amd64 and this fixed the issue.
Installed from Kro4ek Wine-Builds Vanilla
Hope this helps some one else 
Still getting the BLZBNTAGT00000840 Error, switching between versions seems to be working for now, but seriously does anyone have a solution other than swapping between wine versions? I would say this issue is not solved so who marked it as such?
I did, because I’m the thread-opener and its good custom to do so, since the 840 error I reported was solved for me and others.
Edit: And the issue is back with the next update and swapping does not work. People on the US Forums tried another trick that was successful in the past which is described here: Unable to update games with error BLZBNTAGT00000840 - #30 by KasiKuula-2657 - Desktop App Bug Report - Blizzard Forums - please also read the replies. For this to work you need to have an older agent version in your directory. I had one and there was no need to fix anything, the update just worked.
This is again not a permanent solution, sooner or later we will need the updated agent. I would have preferred the version-swap-around.
This thread BLZBNTAGT00000840: Something went wrong with a file - #44 by Crimsond-draenor - Technical Support - World of Warcraft Forums has some more workarounds. That’s all we’ll ever have: workarounds. Wine is a work around the fact that we do not use Win. Blizz can do a rug-pull whenever they feel like it. Some people report that using proton-experimental fixes this. I did not try but maybe there’s hope.
