Standard apps downloaded by webbrowser as .dmg don't start (MacOS Monterey 12.3.1)

Some more info what I tried at my free weekend to solve the problem:

• updated MacOS to Monterey 12.4

• restarted the Mac multiple times

• downloaded DBeaver (one of the apps that didn't run, see initial post) via browser: https://dbeaver.io/files/dbeaver-ce-latest-macos-x86_64.dmg

• started by double-clicking the downloaded .dmg file in the browser and click the app icon (with and also without moving to /Applications): dock icon starts bouncing, Warning "CoreServicesUIAgent Connection from process XXXX does not have the required entitlement com.apple.private.iscsuia", dock icon stopped bouncing, app does not start (same behavior as in my initial post)

• opened the .dmg via terminal: open dbeaver-ce-latest-macos-x86_64.dmg -> same behavior

• started the .app via terminal: /Applications/DBeaver.app/Contents/MacOS/dbeaver - nothing happens, no output, terminal hangs forever.

• checked the executable (x) flags via ls -al - it is set

• checked and removed quarantine flag in DBeaver.app: within /Applications/DBeaver.app/Contents/MacOS: ls -al@, xattr -d com.apple.quarantine dbeaver, as well as xattr -r -d com.apple.quarantine DBeaver.app/ - done, but app doesn't start either

• downloaded the app via curl: curl -O -L https://dbeaver.io/files/dbeaver-ce-latest-macos-x86_64.dmg and started via Terminal "open dbeaver-ce-latest-macos-x86_64.dmg" or Doubleclick in Finder -> works as expected.

• downloaded again via web browser, removed the quarantine flag via "xattr -d com.apple.quarantine "dbeaver-ce-22.0.4-macos-x86_64 (1).dmg", clicked .dmg in web browser and clicked the .app without moving it into /Applications -> works! If clicked this .dmg in web browser, moved the .app to /Applications and run it from there, it does not start.

• mounted this .dmg via terminal hdiutil attach "dbeaver-ce-22.0.4-macos-x86_64 (1).dmg" and started via terminal "/Volumes/DBeaver Community/DBeaver.app/Contents/MacOS/dbeaver", the app started once normally and printed a lot of infos. ok I said, then I wanted to do the same with the .dmg with the other .dmg with the quarantine flag bit being set. But since then I'm unable to start any app successfully anymore: neither per browser, nor by terminal (open, curl, execute)! What's going on here? Apple seems to store hidden information which makes it impossible to debug and reproduce.

• btw., other apps seem to have the same problems on Bug Sur, e. g. here: https://github.com/beakerbrowser/beaker/issues/1861

• I didn't try but I'm sure that all other apps shows same behavior.

In the result, the quarantine bit seems to be one key of the problem. But, as written above, also downloads without that bit set being set didn't start anymore.

Maybe someone could try to download one of the .dmg files in my initial post and try to start the app in Monterey and post here if it works? Thank you. I'm searching now for weeks for a solution and still don't know how to build a new version for our customers who are waiting for a solution.

Again me, some good new this time, after some coffee ;-)

Short summary: The obvious way of downloading of and starting a .dmg was NOT working on my machine (bouncing dock icon without starting the app). I went on with copying the .dmg (let's call it "test.dmg") from /Downloads into a new folder and did a "open test.dmg". This doesn't work either (same effect).

Now, again I went on with "hdiutil attach test.dmg", followed by one of the following launch commands:

• /Volumes/test/test.app/Contents/MacOS/test
• open "/Volumes/test/test.app/Contents/MacOS/test"
• open "/Volumes/test/test.app"

And suddenly everything works, for all apps. Cool! Now I can start apps downloaded with a browser, without quarantine bit modifications. But for "normal" customers also the "click" solution without mounting should work since nobody wants to open a terminal and start scripting ;-)

So, the last, and completely different open question is: Why is the .dmg not launched using the intuitively way: clicking the .dmg, (move the .app to /Applications and) click the .app?