I can confirm exactly the same situation, My version now are:
Windows 11 Pro Custom Desktop 23H2 V10.0.22631.2715, Firefox 120.0, ESET 17.0.10.0, Sandboxie V1.12.1 (it's a beta version to see if the problem is fixed, but it is not a Sandboxie problem).
I sent a support email to Microbe (Australia's agent for ESET), with no solution yet.
Originally Vivaldi and Firefox were affected, but I read some posts on Sandboxie GitHub and on this Forum, and found that turning off Banking Protection and Browser Privacy & Security fixed the issue for Vivaldi, but not for Firefox.
I declined to turn of Browser script scanner, because it looks like an essential piece of protection. But when I did turn it off a few minutes ago, it fixed Firefox as well.
PROBLEM 1: But that is a very poor solution, because Browser script scanner should never be turned off. The Information circle next to it says, "If enabled, all JavaScript programs executed by interbet browsers will be checked by the antivirus scanner."
I am now turning it on again, and I will avoid Firefox until this is fixed, which is a real nuisance, because I normally use Firefox quite a bit, in particular for banking.
PROBLEM 2: I don't use Safe Banking & Browsing at the moment, relying instead on Sandboxie with Ramdrive sandboxes, my VPN (PIA) and CCleaner. But I would like to be able to use it in the future.
PROBLEM 3: I have not been able to test out the Browser Privacy & Security feature, but I am not at all pleased that I cannot use it.
Can we please have fixes to all this as soon as possible.
