Warning: This does not correct developer mode, but "avoids" it. You must be out of developer mode before using this.
Here is a quick batch file I made to copy your existing save files first into a safe folder. This way if the game crashes you can just disable cloud save and replace the folder and continue where you left off. I've already been screwed by developer mode twice so I wanted to help other people.
Where you see a question mark replace with your current directory / folder. Remember if your directory has a space in it, use the " marks.
Replace the steam link below with your shortcut to your desktop.
If done correclty it will copy the files and start the game. You can even turn on cloud save if you want, it won't matter anymore.
Paste the script into notepad and save the file as "DOOM-FIX.bat" or whatever you desire, make sure to use the " marks.
Now just make a shortcut to your desktop and run it, you are not DOOMed anymore. It doesn't matter if you crash and it syncs to the cloud, you now have a safe backup copy of your saved files.
@Echo Locating DOOM save directory.. @Echo Copying save files to safe location.. @Echo off cd \ cd C:\Users\? cd "Saved Games" cd "id Software" cd DOOM xCOPY /e /Y * "C:\Users\?\Documents\?\" timeout 10 start steam://rungameid/379720
UPD: Check this guide - Developer Mode Fix!