Clementine cannot detect some folders with music

Do other folders with OGGs in them show ok?
Are the undetected folders next to detected ones?
Are you the folder owner of the files? (ls -la foldername will tell you).

Thanks

Others are fine.
Undetected next to detected, yes.
I am the owner and filers are also in my group.

Example:
Non detected : Foo Fighters - Greatest Hits
Detected: Foo Fighters - The Colour And The Shape

any suggestions?

sudo add-apt-repository ppa:me-davidsansome/clementine
sudo apt-get update
sudo apt-get install clementine

Then use:

tools -> rescan library

From the top menu after closing and reopening the application.

Did the update and the rescan and still cannot see the folders and the music.

It may be related to how Clementine uses the tags; I made a copy of the non visible folder, edited the tac of one song,placed inside a folder labeled "Foo Fightters\Greatest Hits" and sudendly Clementine sees the original and the copy.

If I remove one I copied then Clementine goes back to not seeing the folder.

What is the next step?

Install easytag and check the IDv3 and IDv2 tags

I had this problem with Clementine a while back and discovered that after I transferred files to my music directory Clementine was placing them in Various or Unknown and we're talking about albums I've bought on Amazon, which should have the right meta information. I had edit the top four entries of each song, Song, Album, song number, and Artist, I didn't bother with genres or other tags. When I saved the information for the first song it dropped that song and a new album entry into the right place in the album list. I have to do this for every song otherwise it stays in the Various or Unknown directories. A bit of a pain but at least I can organise things better.
Hope that helps.