I use NBRT v. 5.1.0.26 with Norton 360 v. 20.4.0.40 and WinXP v. 5.1.2600 & SP3 v.3264.
NBRT boots fine when created directly on a USB stick but it absolutely refuses to work from an ISO file in a multiboot environment. I have 2 rescue boot sticks, one with XBOOT and the other with YUMI and on both NBRT seems to boot at first, it goes to "Starting Windows" but soon after the yellow screen appears this message comes up: "NBRT failed to launch. Required file not found. Program will exit [ERR-0001]", which is a pretty useless error message because it tells you absolutely nothing!
Please do not refer me to previous related posts, I have checked them all and even those marked "Solved" do nothing for me.
I have another WinPE based rescue ISO for Macrium Reflect which works flawlessly from both sticks, so I assume that WinPE can be ruled out, especially since the problem occurs only in the desribed multiboot situations. All other rescue ISOs (Seatools, DiscWizard, Partition Wizard and several test and diag utilities) also work fine and so does a Linux Live distro.
George