Are you shutting down all non-essential programs (especially anti-virus) before starting the game? Firewalls have caused conflicts (generally on loading screens, though).
A couple of people have had BitDefender falsely flag the EE as ransomware, and block it from creating files and folders (in that case, adding the game and My Documents Larian Studios folder to the trusted app and directory section of BitDefender fixes the problem).
Try checking your drive for errors. In Windows Explorer, right click the drive and select Properties, switch to the Tools tab and click Check Now in the Error-checking section.
Try browsing to the '..\Documents\Larian Studios' folder and deleting the 'Divinity Original Sin Enhanced Edition' subfolder.
This folder contains the saved games, configuration files and a level cache folder. Normally I would suggest renaming the folder for troubleshooting purposes, but if you don't have any saved games that isn't an issue.
Next, extract the replacement folder from the download below into your '..\Documents\Larian Studios' folder. That should at least let you start the game, but you would need to check if you could create a new profile or start a new game and save and load properly.
https://www.dropbox.com/s/1ipz4q9780x35tj/DOSEE_doc_20119430.zip?dl=0The graphicSettings.lsx file is set to 1280x720 Windowed mode, Very Low quality preset, which you can change in the options (manually, or hit autodetect) if this gets the game to start and you don't have any further issues creating folders.
If that doesn't help, delete the downloaded My Documents D:OS folder.
Try creating a new Windows administrator user account, leaving the My Documents folder in the default location, switch to that account, and then start the game directly from the '..\SteamApps\common\Divinity Original Sin Enhanced Edition\Shipping\EoCApp.exe' program file, by right clicking and running as administrator.
If that lets you start the game, that would mean there was either a problem with the current user account's My Documents folder, or a conflict with something running in the background.
