Just to clarify a bit on PostgreSQL versions on Mac:
Starting in Resolve 16.1, we are using a newer PostgreSQL installer in the Resolve installer.
For a long time, the Resolve installer installed PostgreSQL 9.5.4 (when you selected PostgreSQL Server installation in the Customize area).
With the arrival of Catalina, we had to update to PostgreSQL 9.5.19. 9.5.19 supports Mac app notarization, which is required in Catalina.
Note that 19 is a newer version than 4. It's not 1.9.
The Resolve installer will not install PostgreSQL, if there is any version of PostgreSQL already on the system. If you want the Resolve installer to install PostgreSQL, then you'll need to remove PostgreSQL from the system. Before doing that, make absolutely sure something else on your system is not already using the current PostgreSQL version for something, and that it doesn't have any important data in it.
Assuming you are OK with removing any existing PostgreSQL version, and you are sure any important data it may have is backed up, the following process should be followed:
Trash the /Library/PostgreSQL folder.
If there is a PostgreSQL folder in Applications, trash that as well.
Empty the trash.
Open a Terminal window and run:
sudo dscl . delete /users/postgres
It will ask for a password. Password should be you Admin password.
Now the Resolve installer should be able to install PoatgreSQL.
Make sure you are using a Resolve installer version of 16.1 or higher.
Run the installer. When you get to the Installation Type step, select the Customize button in the lower right.
That will expose a window to select additional items to install. Select PostgreSQL Server.
Continue the install. (BTW: You can run the installer of your current version without issue, i.e. if you have Resolve 16.2.1 Studio installed, it's not a problem to run the 16.2.1 Studio installer again for this process. It will not affect your current Resolve install.)
Now open Activity Monitor, and in the View menu, select All Processes.
Sort the Process Name column and look for multiple postgres processes. If you see those, PostgreSQL is running.
If you don't see those, reboot the system and open Activity Monitor and check again. Hopefully you'll see multiple postgres processes. If not, PostgreSQL is not running, for some reason.
Note that the PostgreSQL 9.5.19 install process no longer creates a PostgreSQL folder in Applications. So don't be alarmed if you were expecting that, and it's not there.
Which means there is no pgAdmin app installed. If you have a desire for pgAdmin, you'll need to download and install pgAdmin4. The current version of that is here:
https://www.postgresql.org/ftp/pgadmin/ ... .21/macos/