Wow, I can’t believe I didn’t know this. I’ve been using Script Debugger since version 3 and it was certainly an enabler for a newbie scripter. Since retiring I don’t use Applescript very much now, but it still powers many things I do.
Sad to see it go, but glad they’ve made the latest version available. It will be a very sad day when an OS update finally breaks it.
Thanks, @Dafuki. My scripts are now rescued.
So I started with the updates, first my iPhone from 26.3.1(a) to 26.4. It took about 20mins. Then I did my M5 MacbookAir. That took about 15mins. My Apple Watch Ultra, that took hours for some reason. I took it off my wrist, noted it at 65% battery so I put on charger and the update status was at downloading. I revisited the watch after 30 mins to find it was at verifying. I walked away.
The longest times were with my Home Pods. Each showed about a 1 Gigabyte file update. From the iPhone Home App, I noticed orange rings as progression and for downloading…they barely moved once at half way. I was up over an hour when I noticed the first of two Homepods rebooted. The second Homepod took another 20 mins. Then it rebooted and lit up my bedroom for what seemed eternity.
I now just ran Timemachine on this Studio as this morning, a notification popped up that 26.4 is available… 8.73GB. Guess I’ll make coffee…
I updated my M1 MacBook Air to Sequoia 15.7.5, and it’s the first update in years where I’ve run into minor glitches. In the few days since I updated, I’ve had a couple of apps fail to launch, though they launch fine after rebooting the machine. Has anyone else seen this behavior?
I’m curious, since it sounds like this would be a good thing to encapsulate in an article… Above, you said you created a new script and Script Editor had problems opening it after the first try. How does that fit in, since I presume it didn’t have any weird binary in it?
After reading the second observation, I now believe that this is a bug in the Script Editor app, not necessarily any problem in the script itself.
If you have personally observed this (not just read this article), please let Apple know via Feedback or some other bug reporting mechanism, since they may not yet know about this bug.
Yes, I’ve seen that a handful of times in recent years. Sort of got in the habit of restarting after the install restarts itself. And if any quirks pop up, maybe go the whole thing and log out, log in, shut down, have a cuppa, boot, restart and then see.
Oakley’s post might be useful background…
I looked at this issue twice. The first time, which you’re referring to, was cursory and in retrospect a little confused. The second time I spent an hour or more exploring the behaviors. The answer to your query is in the second longer post: if you attempt to open a “bad” script Script Editor will silently fail to open it and then it will not open “good” scripts again until you quit and re-launch Script Editor.
Dave
Yes, I think it is a bug in Script Editor, too. The facts that the scripts run without error and Script Debugger can open them points to a problem with Script Editor itself.
I plan to report this later today after a couple more cups of coffee… 
Dave
Thanks. It seems to be an issue with “first launch” app behavior specifically, since the machine has been shutdown and restarted a few times.
It’s hard to pin down, since most apps have been fine. Come to think of it, I may be remembering something like this involving apps forgetting where their libraries were. I’ll do some more digging.
Me either! I don’t do a ton of AppleScript, but Script Debugger was definitely my editor of choice. I feel a little guilty now that I never registered my copy (I guess I lived within the restrictions), and especially since they’ve now posted registration codes on the download page. Maybe I’ll see if there’s a link to a “retirement fund” somewhere on their site. 
Ah, but the build number changed—it’s 233 in 26.3.1 and 234 in 26.4. So Apple may have touched something.
Ah ha! Missed that! 
Dave
I encountered this issue when I installed MacOS 26.3. Luckily, I found this solution online. I hope they fix this soon.
I like listening to music on my long morning walks, so was looking forward to trying Playlist Playground. I gave it a few suggestions and it created a pretty good playlist for me! You can refine it after creating. I think it’s a pretty cool feature.
By the way, the region restriction should actually read, “those who set their region to the U.S.” I do that because Apple News also isn’t available to those whose region is in Japan. So my account is a U.S. account, and Playlist Playground works fine for me here in Tokyo.
I updated and can report that my scripts work. My oldest on this Mac is from 29 January 2022. No problem opening scripts in ScriptEditor either.
Edit: Look here for Adams’ article on this: macOS 26.4’s Script Editor Won’t Open Some Older AppleScripts
Another minor problem I’ve found in MacOS 26.4:
AppleScript for the TV app seems to be at least partly broken (or, as we’d say here, “munted”). The “selection” application property always returns an empty list, even when several TV episodes are visibly selected.
I’ve submitted this in the Feedback Assistant.
While obviously no one outside Apple can guarantee it, this seems pretty unlikely. None of the AI tools they offer now run in such a fashion even within Apple’s own applications, there doesn’t seem to be any market pressure that would make them change that, and it seems extremely implausible that a future macOS release would somehow reach into BBEdit or Emacs and edit text without our permission.
My M2 MBA has Sequoia 15.7.5 installed but only Safari 26.3.1 and I can’t find a way to update Safari to 26.4. Perhaps Safari 26.4 only works with MacOS 26.4?
Try refreshing and checking for updates again. For whatever reason, when I updated to 15.7.5, the Safari update needed to be installed separately, even though I originally selected both 15.7.5 and Safari 26.4 in the “other updates” section.