In general, if the problem is with the launcher after today's update, running from the executable should work.
Deleting the contents of the launcher's cache folder may fix the crash when starting from the Steam or Galaxy client: 'C:\Users\<UserName>\AppData\Local\LarianLauncher' (copy and paste %LocalAppData%\LarianLauncher
into Windows Explorer to quickly open that folder).
File EoCApp.exe is NOT present in the DOS2 DE bin folder, only in the classic folder. ...
Steam always "re-downloads" a "non-verified" file, but it's the same problem.
Is there a SupportTool.exe file in the '..\DefEd\bin' folder?
Try temporarily disabling your anti-virus program, or add an exception for the game's install folder, and verify files again (or in the anti-virus program, you should be able to un-quarantine the executable, assuming that is what happened to it).
If that doesn't help, try doing a clean boot and then verify files. Click Start, or hit WinKey-R, type in msconfig and hit enter; in the General tab, click Selective Startup, uncheck Load startup items (if required) and leave Load system services and Use original boot configuration options checked. Next, click on the Services tab, check the box to Hide all Microsoft services, then click the Disable All button (maybe make a note of which are currently enabled/disabled), then click OK and reboot the computer.
Run msconfig again to switch back to the normal boot configuration.