I have received this installation error attempting to upgrade from MacOS 26.4 beta 2 to beta 3 on my Intel 2020 27” iMac, and now trying to install beta 4 from beta 3 on my M1 Max MBP. I have seen from a sprinkling of post that some others have had the same issue. I was able to successfully perform the 2 to 3 upgrade on the iMac in safe boot, suggesting possible compatible, third-party app. But that did not work for beta 4 on either device. I have submitted feedback for each episode. Any others have this issue? Unusual for Apple, I have never had any issues installing beta software before.