Why do I see an error message advising that the file “cannot be opened because Apple can not check against vulnerable software…” when trying to install under Mac OS Catalina or Big Sur?

This information applies to version(s): 2, 3, 4, 5, 6

All our versions are signed and notarized, so this normally never appears. However, in the case of older versions: What you are seeing is part of the new security protocols Apple implemented starting in OS X 10.15 Catalina, rather than anything initiated by DxO PhotoLab. You will need to do the following:

• Open OS X System Preferences.
• You may have to click on Open 'Security & Privacy'.
• In the lower part of the screen, you will see “OpenAnyway” next to the explanation that DxOP PhotoLab is blocked.
• Click on “Open Anyway”. You may have to click on the lock icon in the lower left part of the Systems & Preferences window and type in your system administrator password. This may or may not be your user account password depending on how your system is configured.
• Another popup will appear again asking if you want to open it: select “Open”.