What does the "Unexpected file format." error mean?

[Chaplain Dale]

When I try to open any html file in dreamweaver CC I get an "Unexpected file format." error.  This has never, ever happened before and this error appeared after CC updated this morning 4/18/2022.  I cannot find documentation in Adobe for this error.  

[Nancy OShea]

Restore Preferences.

https://helpx.adobe.com/dreamweaver/kb/restore-preferences-dreamweaver.html

Also make sure your local site files reside on your primary computer drive, not cloud drives or zipped folders.

[Chaplain Dale]

Nancy,

I uninstalled Dreamweaver CC and when it asks you to keep your preferences or not, you definitely need to say no.  Now Dreamweaver CC is working.  But, I had to re-install my store and other stuff.  Thanks for the help.

[Nancy OShea]

Sometimes updates & 3rd party extensions cause the Preferences file to become corrupted.  In a decade or more, I've only had to restore preferences a few times. It's not usually needed. 

[Chaplain Dale]

Thanks for your help Nancy!

All the best,

Dale