This is a separate issue from the SensApi.dll, which did not affect me. There are no error messages displayed.

With extensive testing and after following all the suggested repair and fix procedures, I could reproduce the issue by myself on both Win7 64 and Win10 with the latest version (Sandboxie-Classic-x64-v5.53.3) installed.

It only happens if the game is run in Sandboxie, which I use to keep my OS clean from unnecessary installations, unwanted orphan files by programs and games and keeping access to my documents folder isolated from such (for example addons in ESO).

If the Steam client and the game are launched outside of the sandbox, the game runs normally and works without issues.

If started inside the sandbox, the game runs for just a few seconds before exiting without any error messages and returning to the launcher, even when just staying on the login screen without doing any action.

This applies both to Live and PTS.

At the moment my hypothesis is that this could be somehow related to the last minute "Implemented additional anti-cheat measures" patch addition, since others have had troubles in emulated or sandboxed environments, like Win 7 64 in Wine under Linux.

I've been running this setup for years and more than 11.000h of playing so it's been fine until the latest patch and nothing changed on my part (booted the Win7 64 Os that worked the night before, patched, had this problem when servers went live).

I used Process Monitor and tested it a few times: eso64.exe always exits with "Exit Status:-1073741819"

Please check what went wrong