Installed on two windows setups, one just as normal the laptop came up and said unable to close un named programs and would need a reboot. That was odd as the laptop had just rebooted from the January MS updates and the desktop, which had no such message or reboot needed had been in use all morning.
I wonder why PL is now needing this type of install after not for so many years.
It could be that antivirus software or automatic backup software or another background process was using files that the PhotoLab installer modifies. Windows couldn’t identify the other software that was using the files and couldn’t shut it down cleanly in order to complete the install process without a reboot.
There was somthing but what I dont know as same security on both and the one that needrd a reboot was newly rebooted after MS updates. I had the same with the original V6 install and I never seen why that happen ether. Unlike the user who found data problems after it happened to them a quick check as expected found all the photos in place.
But background software doesn’t run all the time. It runs on a schedule, and sometimes you don’t know the schedule or what files are being scanned or used. And updates can continue to run in the background after a reboot.