UPDATE FOR THOSE STUCK ON 92% and or any % TRY THIS

BG3 - Stuck Download (Workarounds and Solutions)
[Depends on your game and problem variant]

(EDIT like 15 - I've noticed some people are finishing the install with only 106.25 GB it should be at least 108 GB, so just take note I don't know what that might be breaking as others have stated, so far no one has commented not to do such because it broke their game, so until then ehhh)

Base Information:

PS: You may have to ShowFileExtensions if you do not by default to see which is which.

Solutions/Workarounds:

READ ME FIRST: Make sure to close GOG-Galaxy beforehand. Once you have deleted, changed and renamed the needed files reopen and let it do its thing. (Some people will not need to change/delete anything but one file) then it should finish!

1. Cloudlen's Combination Solution - He/She combined the other three into one.

* Delete gustav.pak.state

* Rename gustav.pak.download to gustav.pak

* Delete game.pak.state

* Rename game.pak.download to game.pak

* Open /Baldurs Gate 3/!Temp/ or just /Baldurs Gate 3/ (If !Temp folder is there, use it! not the main) and delete... the .hashdb files and something like 2bafjdjgj3o2340gjsjsfjk (264 kb) the name will be its own not what I typed here, I deleted that too. (not the .info or folders) 2. Partakith's Initial Solution

* Open /Baldurs Gate 3/!Temp/ or just /Baldurs Gate 3/ (If !Temp folder is there, use it! not the main) and delete... the .hashdb files and something like 2bafjdjgj3o2340gjsjsfjk (264 kb) the name will be its own not what I typed here, I deleted that too. (not the .info or folders)

* Head into the /Baldurs Gate 3/Data/ and change Game.pak.download to Game.pak should be about 1.2 GB in file size. Mentioned it prior did not think it would be an issue overall. May need to do this first idk.

Thanks to @Battozai for mentioning it may be different .download files for others.

3. Battozai's Combo Solution 4. SamF18's Solution (Need steam copy as well)

Thank you to everyone that got involved and kept it to the point allowing this to progress into multiple different solutions!

Please comment if this worked for you, to let me and others know!

READ ME AFTER -

Getting a Data Mismatch? Find out what's causing it by following the steps here:
https://larian.com/support/faqs/the-launcher-has-a-data-mismatch-error_78

In short open "%LocalAppData%\Larian Studios\Launcher\Cache" via Win+R for ease
Find the latest _alteredFiles log file open it and it will tell you.

EDIT - DONT DO THIS PART OR IT WILL GET STUCK AGAIN (Making the above changes does not fully fix the issues at hand, users checked and got stuck on 91 instead of 92 when trying to verify)
Here is what to do after the solutions to ensure it’s correct

Thank you for posting this. Where did you find the temp folder? All I have is D:\GoG\GOG Galaxy\Games\Baldurs Gate 3 and that's where I find the .hashdb file. I deleted and restarted Galaxy, but that did not change anything, it's still stuck at 92%.

In my case same as above.

it was in my Games\Baldurs Gate 3\ Folder as I had the Beta so it I guess it would likely be your main folder.

There is also another file that is not a .hashdb but something like 2bafjdjgj3o2340gjsjsfjk (264 kb) the name will be its own not what I typed here, I deleted that too. then restarted GOG, let it download for a second, paused it on purpose and restarted it a second later..

Because it worked all of that is gone for me, so I have to go off of memory :/

Steps 1 and 2 but its was Gustav.pak.download i had to rename to Gustav.pak that worked for me. guessing files with .download should go bye bye

thx @Partakith

Well now its just stuck in a 10 gb update... searched for .download and deleted it.. works

Worked for me as well! Thank you!!!

Solution seems to be:

Shut down GOG completely

Go to game folder : ex.: C:\Program Files (x86)\GOG Galaxy\Games\Baldurs Gate 3
Search for .download
Delete .download in everything that shows up

Launch GOG.

Should finish download at this point.

Look it GOG has an update for the game and download this
If it gets stuck, do the same as first time

Is working for me now

----
first quit gog,
delete gustav.pak.state
rename gustav.pak.download to gustav.pak
delete game.pak.state
rename game.pak.download to game.pak
delete in Baldurs Gate 3 folder the .hashdb and the other temp file but not the folders or .info files.
restart gog galaxy and BOOM it worked!
I hope it'll work for you !
-----

This worked Thanks
As someone else mentioned, below is the solution.

first quit gog,
delete gustav.pak.state
rename gustav.pak.download to gustav.pak
delete game.pak.state
rename game.pak.download to game.pak
delete in Baldurs Gate 3 folder the .hashdb and the other temp file but not the folders or .info files.
restart gog galaxy and BOOM it worked!
I hope it'll work for you !
""

Did the trick.
Mention: The gustav files are in the "baldurs gate 3/!temp" folder, not the gustav files that are already in the /data folder.

I tried all of the above, but getting a data mismatch when I try to start the game.

I do too, but it runs and is updated just fine but I had the beta so I kept some of the beta files so mine makes sense.

Thanks Partakith! This worked for me.

Thx now it`s work <3

Option 3 is a pain.

I broke down and did it. It finished the install.

I'm doing a verify and repair right now. Not sure if this is a good idea or not but I don't want a corrupt installation. I'll let you know if it verifies okay or if it breaks and gets stuck installing again.