Thanks for your reply!
None of the Norton processes seem to use any more memory or CPU resources when Shortcut is running. The only program specific white-lists I can find only relate to communication firewall rules, not anything to do with the anti-virus or just running the program. Norton does accept Shortcut’s install program as a “trusted application” based on automatic customer feedback.
I looked at the Windows compatibility settings for Shortcut, but there was nothing there that looked reasonable to try. I sure don’t want it, or anything, to ever run in Windows 8 compatibility mode!
This evening, I was able to process a small file with Shortcut just fine - but like I’ve been seeing it totally bogged down and the UI pretty much stopped responding once I loaded a 5GB input file.
All of my 4 hard drives are formatted with NTFS, using different allocation unit sizes depending on their total size and what’s on them. I just replaced one of the 8TB drives (the one where most of my videos are stored) with a new one, because the old one had been spinning for over 30,000 hours and its brother drive failed a couple of months ago. I formatted the new drive with a 256kb allocation unit, while my other 8TB drive was formatted with a 128kb unit size. I copied one of the input files from the one with the big allocation unit to the smaller one, to see if Shortcut worked better with it on that drive. Well, not really - it still ran through the steps I did on the UI like a stuck pig, much slower between mouse clicks than I would normally expect - so no conclusive differences there.
I may try to download another free, open source video editor to see if it can process the same input files better than Shortcut is currently able to do. Problem is that when I was looking around and found Shortcut several years ago, most of the other ones sucked by comparison. I’ll look around again but If I’m desperate I may try the bloatware one that Microsoft shipped with Windows 11, ClipChamp, which I deleted but wouldn’t expect too much from…
I’ll keep this thread posted, and again thanks for your help!