So after continuous crash i got yesterday i try to do "Scan File" on my BDO files.
i have to download from 742.PAP all over again because of this.
after checking the Update.log file i saw an invalid PAZ file. it looks something like this: 

The Patch won't continue if the .PAZ file isn't fixed. and the launcher will always throw you "Failed to apply patch" Message
is there someone willing to upload their working PAD03934 File?

Edit: After Numerous Trials and Crash. i have Finally Fixed the Problem. Here's Ways to Fix it:
- Run a File Scan. Wait Until it's Finished or Failed it's all the same.
- If the launcher pops a message "Unable to install Full Client" or "Failed to integrate the Validity of the game files" or something like that, Close the launcher.
- Go to your BlackDesert File and you Should Find Update.log file

- Open it and Scroll all the way to the bottom until you found a log similar to this:

2020-04-05 12:44:35 [INFO ] different file size: Paz/PAD02916.PAZ(13, expected: 8300076)
2020-04-05 12:44:35 [ERROR ] failed to replace package: Paz/PAD02916.PAZ

- Open your Paz file Located in the Black Desert Folder

- Find the .PAZ folder that's causing an error (for example on the top. the .PAZ file that's causing the error are PAD02916.PAZ) and delete it.

- Re-open your Black Desert launcher and it should restart the Full Client installation.

- It should be Downloading the Corrupted files you deleted.

- If things are Okay and No More Corrupted files the Game should start normally. If not, then go back to step one and repeat it until you could Launch the game.

- the Paz files should be different every time you found an error while "File Scan" or Patching.

i hope the post somehow helps people out there who struggle applying a patch or some sort. it might won't work for everyone but you could try if ya want to^^

Noted.

Thanks for the awesome guide.

Will let people know if they got problem during patching.

Hi guys,

im facing the same issue, i already did as your explanation but the problem still there.

So for example the error was on this PAZ file PAD00005.PAZ, i did as your explanation and the problem solved then after 1 or 2 hours of playing the game the error will happen again but on another PAZ file like PAD03242.PAZ

And now everytime i do scan files it will always download the file around 3.13 GB all the time

and i already did this for almost 20 times in 3 days

is there any other solution?