I was able to install both Installation Manager and RDi on Catalina, but after upgrading to Big Sur - Installation Manager is not working. It launches with a blank window with the text "Failed to create the part's controls" and a dialog with a java.lang.NullPointerException.

RDi that was installed on Catalina prior to upgrading to Big Sur is still working, but I need Installation Manager in order to upgrade RDi.

Anyone using MacOS Big Sur and RDi/Installation Manager successfully?

IBM Installation Manager currently does not run correctly on macOS 11 as it and RDI were created for macOS 10 (OS X). The RDI installer itself was build for Sierra.

The IM team is working on a solution for Big Sur but there is no fixed ETA at this time. Keep an eye on this document:

https://www.ibm.com/support/pages/node/6373030

Haven't seen any more information on this - however I was now able to install the latest IBM Installation Manager 1.9.1.5 (1.9.1005.20210309_1755) on Big Sur, and also RDi 9.6.0.10..