10049 killed my SP3.

I know what I'm doing. All my data is in the cloud, so nothing is lost. The only thing I really lose is time and I have plenty of that.

I'm sure you do, but using hyperbole llike it "killed" your SP3 warrants responses like this
 
I had the same problem with my SP2. Create a new local admin profile and log in with it. Delete your main profile. Recreate your main profile. When you log back on, it'll be fixed.