For the Steam version, in the library right click the game, select Properties, switch to the DLC tab and make sure 'Divinity Engine 2 Data' is checked off to install.
Is there any difference if you try to start the editor directly from the '..\SteamApps\common\The Divinity Engine 2\DefEd\DivinityEngine2.exe' program file, by right clicking and running as administrator?
In the '..\The Divinity Engine 2\DefEd\Config' folder, try renaming the Config.xml file to bring up the prompt to enter the data path again. Usually a problem with that (accidentally pointing to the Classic data, for example) causes a crash on startup, though.
Try doing a clean boot and then start the editor directly from the DivinityEngine2.exe executable. 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.
If you check the Event Viewer, does that give an error code or 'Faulting Module' file name that might help identify the cause of the crash, if it is crashing?
- click Start (or WinKey-R), then type "event viewer" into the search box. in Windows 10, 'event' should bring up 'View event logs'.
- after starting the Event Viewer, expand 'Windows Logs' in the left column and select 'Application'
- in the center column, look for a recent error for the game (maybe sort by Date and Time, or search for 'DivinityEngine2')
- check the information under the 'General' tab below the list of events, starting with "Faulting application name..."