Since upgrading to macOS 26 (Tahoe) Roon (2.54 build 1554) sometimes - but not always - needs to be launched more than once (from the Dock). On other occasions, it seems as though there is a brief 'white flash' of the Roon window visible on the desktop; and then Roon launches. Once launched and running, everything seems to work perfectly. Thanks!
This is a known issue as of now and the fix is about to come soon.
As of now the only thing that can reduce amount of crashes on the start is Rosetta Compatibility mode.
In order to get it please go to the Apps folder (Cmd + Shift + A from the desktop or finder) and the find Roon, select it and Get Info (Cmd + I). There you will see an option “Open using Rosetta”.
If those crashes are critical for you at this moment you may try to stick to abovesaid until permanent fix comes out.
Thanks for the kind words, @Mark_Sealey ! Yes, our devs are aware and have a ticket in their queue regarding this, and we hope that the issue will be sorted out as soon as possible.