Filename to tag not working

I have an album of MP3s that have been mistagged - the artists names and song titles don't match the actual song. The filenames however are correct. When I try "Filename to tag" conversion, it shows "%artist% - %album% - %track% - %title%" in the format string, which appears to be correct. However, the OK button is greyed out. I really don't want to have to rip this CD again. What's going on here? Thanks.

It is greyed out when the formatstring doesn't represent the filename. What is you filename? For %artist% - %album% - %track% - %title% it would have to be someting like "Michael Jackson - Thriller - 05 - Beat It.mp3"

Yes, that was the issue, the tags in the filename weren't separated by dashes.