That is what exact happens to me and others too. Went through this meanwhile also with help of the support team. It seems to be like this, depending on the size of your database, mine was more than 2 GB and the spec of your Mac, that it could really last more than a cup of tea. Maybe a good advice could also be to do this during the night. You may like to read also my post to this, PL 4 stuck after start while importing database and parameter
Or just follow this instruction, for a quick and dirty solution.
- If you want to use PL 3.3 also in future
- move the database ~/Library/DxO PhotoLab v3/DOPDatabaseV3.dopdata to the desktop
- trash the already build ~/Library/DxO PhotoLab v4/DOPDatabaseV4.dopdata
- trash also ~/Library/DxO PhotoLab v4/DOPDatabaseV4.dopdata_output
- start up PL 4
- move PL 3.3 database back
This way you will start from the scratch. But if you like me, don’t have used keywords or such, this works fine.