iPhoto library manager upgrade

If you're running Catalina iPhoto will not work so you must be using Photos. For a Photos library one requires PowerPhotos instead of iPhoto Library Manager.

However, if you have iPhoto libraries that haven't been migrated to Photos then iPLM will open them as well as migrated libraries and you can view the contents.

It would help if you told us exactly what your running and what you're trying to do so we don't have to speculate with our replies.

Assuming that you were on the latest version of iPhoto before you got Catalina, you don't need any updating. Simply open Photos with the option key held down. Choose your iPhoto Library and Photos will create a new Photos Library with your iPhoto media. your iPhoto Library will not be changed.

Are you talking about iPhoto Library Manager from Fat Cat software?

4.2.7 is the most recent version.

However, if you have iPhoto libraries that haven't been migrated to Photos then iPLM will open them as well as migrated libraries and you can view the contents.

Does it really work for you, OT? When I try to run IPLM on my Catalina Mac, I am getting a warning:

I have currently no longer the Retroactive version of iPhoto installed, perhaps this is making a difference.

No, I don't get any warning. I can load and view all of my migrated and non-migrated iPhoto libraries.

9.61 is the most recent, you can go ahead and use Photos to convert your library.