Missing Developer.xml
I am unable to change the workspace to Developer mode because the Developer.xml file is blank. Not sure how this happened but how can I get it recreated?

I am unable to change the workspace to Developer mode because the Developer.xml file is blank. Not sure how this happened but how can I get it recreated?

Turn on your operating system's Hidden Files, then follow the path given in the error window you posted...
C > Users > your username > AppData (normally hidden) > Roaming > Adobe > Dreamweaver (your version) > your language > Configuration
...and rename the Configuration folder to Configuration_old.
When you restart DW, it will recreate the folder with fresh copies of the files it holds and should recreate your Developer workspace.
Already have an account? Login
sso.login.detail.descriptionWithRegistrationLink
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.