The non-category plugin did not work for me.
For Multisite WordPress the following works:
\
;/%category%/%postname%/
.
This will display your url as www.domainname.com/categoryname/postname
;yourdoamainname/blog/
. Ignore it. If you save now the work you did in step 4 will be overwritten. This step of opening permalink page but not saving in needed to update the database.