I have posted previously regarding my app which consists of a collection of stay-open app modules all controlled by a primary app. My last post had questions about using script libraries which this community very generously and effectively answered. I re-architected my app suite, deploying a very useful shared script library and breaking up the overall suite into smaller, more efficient modules.
All of this was under macOS Sequoia. I buttoned everything up last week and ran all kinds of tests with performance analysis and Activity Monitor and was highly satisfied with the instantaneous responsiveness of the entire app suite - it was running lightning fast and memory consumption was balanced and efficient.
To review, the overall app uses primarily Numbers for windows displays, plus at times Music and Quicktime.
Now, I just made the (fatal?) mistake a few hours ago of upgrading to macOS Tahoe 26.2. And now my app has persistent occurrences of the dreaded spinning pinwheel. The primary app hangs up at times (when responding to display dialog prompts) for seconds at times when prior to the upgrade those responses were instantaneous. I never saw the pinwheel under Sequoia.
The only change is the macOS upgrade.
What is going on?