Hi Seedy,
I did a clean install of my simulator, and I’m in the beta via Insider Hub. So the initial install was the base sim, and it loaded up to the menu just fine and then it detected the new beta build 1.29.30.0 and said I should quit to update.
After doing so, I downloaded the launcher update from the MS Store/Xbox App and upon launching it prompted the roughly 1.4GB sim update. It was after this point that every time I try and launch it I get the error.
So, I’m not certain it’s solely beta related, but yes, I did do a clean sim install early this morning (via MS Store).
Cheers!