Have you tried this? You should be able to find this info on the forum &/or the wiki but I've had a few vinos so I'm feeling generous.
From the main MC window, navigate to the left side pane and bring up Drives & Devices, then:
Explorer > [locate the file(s) that you're interested in]
Your other option is to navigate via the Video option in the left side pane if the files have been imported to the database.
1. Select your files
2. Bring up the context menu (i.e. right mouse click) and select Library Tools > Fill Properties from Filename
3. Usually the automatic function works well. Review it to make sure that the media sub-type is correct be it Movie or TV Show. If you need to, bring up the Tag data (Alt+Enter) and set the media sub-type to suit. From my experience if the title of the video and the media sub-type are correct, then all should work fine.
For the title, consult
www.thetvdb.org or
www.themoviedb.org to ensure that you've got that point of detail perfect.
4. Bring up the context menu again and run Get Movie & TV Info
I've used the above protocol multiple times and that does the trick. If you have some quirk, you could always delete the side car file (i.e. file ending in "_JRSidecar.xml") and make sure that you're starting from a clean slate.