I just ran into this same PITA how long as windows 11 been out now a year and pearlabyss hasn't done anything about compatibility?  Trying some of your suggestions hope it works because I really don't want to have to play on my lesser machine that's still win 10

This worked for me. 

1. Pop up > Typed Y
2. Cntrl Esc Tab > ended program
3. Program files, opened up launcher 

4. Logged in and it auto downloaded. 

Worked for me too! So far it's installing!

Be aware, if you're a noob like me: at step 3 you need to look for the launcher file (BlackDesertLauncher.exe) in whatever folder you assigned extraction to when you opened the installation file. The automatic setting is C:\PearlAbyss\BlackDesert.

Now lets hope I can officially retire my dusty old computer, and make good use of my new one for BDO :D

*fingers crossed*

Okay, so I got it to work and I had every issue mentioned here including the patching errors (both cannot connect and can't patch) as well the the uninstallstring popup, frozen installer, etc. I also did not have the .exe file that would allow me to launch BDO correctly after "install".

Here's what I did that got the launcher working as normal. No guarantee yet that it plays the game, but these are the steps I took to get this far:

1) Download the installer from the non-steam site after restarting your computer (just a precaution to make sure nothing open can cause issues)

2) Run the installer as Windows 7 compatability as well us as an admin using the compatability tool in the right click menu under more options

3) Select a non-default location (don't know if this helps, but it's what I did)

3) Type y as the answer to the uninstall string prompt

4) Open task manager and kill the registry editor under the dropdown for the BDO installer. This will allow it to go to the finish screen. Unclick Launch BDO and hit finish

5) Restart your computer

6) Go to the installed location and right click the launcher to go through the compatability mode tool again

7) Select admin and compatability to Windows 8

8) It launched the weblauncher for me at this point.

I can't guarantee any of this will work for you, but for some reason using differing compatability modes when installing vs patching worked, when choosing the same ones caused it to fail. This may be a fluke, but it may be a quirk in how they coded some option. I'll update this with if it patched and launched fully once it's done.

EDIT: The launcher was downloading everything fine but stopped midway due to a patch error. Maybe because I opened Discord, maybe not. Once it stopped, I hit scan files and waited while it finished that. Once it was done, the game was able to launch successfully

still does not work. what a game

If you are having trouble installing the game, I recommend reaching out to support via https://support.pearlabyss.com/Support/Qna/Index/PC

Sadly, as you did not post any more information here, it is not possible to help you with any troubleshooting for the game here. But you can always join the BDO Official Discord, and maybe the community can help you with some of the issues: https://discord.gg/blackdesertonline

already reached out, got told if you have windows 11 it's just bad luck. I guess i dogded a bullet by supporting a game that dosent even want to support itself.

this worked for me thanks!

i had it stop at 99% i used control alt delete to close the launcher, then opened the actual game, not the beginner launcher and that worked

you cant install the game without launcher. so there is no actual game, unless you already had the game installed on ur pc.