Calendar App Won't Load At Startup

I have a very simple little (and little-known) calendar program called Ample Notice for Windows by a long-dead computer science professor (Granny's Old-Fashioned Software) that I've used for many years now, through all versions of Windows, including the current Windows 11 Professional. For unknown reasons it suddenly quit loading at startup about a month ago, even though it shows to be activated in the Startup App section in Settings, in the Startup Apps section of Task Manager and even the proper registry entry for it is present (I checked), yet when I click on the program's icon on the Taskbar, after boot and when the Desktop appears, it loads immediately (as it always has). This program is so basic that there's nothing tricky that could go wrong with it. There are multiple other apps that run at Startup with no problem whatsoever. I've tried disabling all of them (save for Ample Notice) and later even reinstalling the program itself (it's 32-bit and not a 'Windows app'). Now here's the kicker: I've got a nearly identical Dell XPS desktop running the same version of Windows Pro (24H2, build 26100.2152) and it loads perfectly at startup - it displays instantly on boot, just like it's supposed to. The problem started well before I updated to the latest version of Windows & I did an in-place upgrade (with an ISO downloaded from the ElevenForum site, by the way) hoping that would fix the problem but it didn't. Of course, I've run the de rigueur DISM & SFC/Scannow tools multiple times and everything comes up clean. Why 1 computer will run Ample Notice for Windows and an essentially identical one won't, let-alone what mysteriously made it stop working (on startup; it otherwise runs like a charm) has got me at a standstill here. Any suggestions would be welcome.

How to Start a Program at Startup using Task Scheduler.

If you want to learn how to start a program automatically at Windows Startup or at specific time by using the Task Scheduler, then continue reading this tutoria

www.wintips.org

you can try to run it via scheduled task and see if it will load. someone else here has this exact issue, but with PowerToys at startup. Works on one pc but not the other. I would say to run the scheduled task at startup, not logon and and check "Run with Highest Privileges" and "Hidden" on the General tab.

Thanks. I'll give it a try. But it's still a mystery as to 1. Why it suddenly stopped working in the 1st place (after literally years of trouble-free operation over multiple iterations of Windows) and 2. Why it would run on essentially an identically-configured computer with no problem whatsoever? Where's Alfred Hitchcock when you really need him?

I installed the program (Ample Notice) on another beat-up old Dell laptop I have (running Windows 11 Pro as well) and it worked perfectly from the get-go, continuing to make no sense whatsoever. I compared all 3 computers at the 'Registry' level and they were identical; it also required putting a shortcut to the app in the 'Startup' folder (same as the other two), due to the age of the program. However (and since then) I've managed to cobble together something with the Windows Task Scheduler that seems to work. But it's still totally crazy that I had to jump through this many hoops for something so simple that works perfectly on 2 other computers. If anybody has any ideas I'd still be happy to try them out and get to the bottom of this thing, though.