Can't add music to Windows Media Player 12

I have seen other postings about this problem, but not solutions.

I run windows 7 and WMP 12.

I have a large number of albums which I bought before CD's took over.
I have purchased a USB turntable and I am creating mp3's of the vinyl.
The creation of mp3's works fine. They play in wmp fine and sound
good.

When I take the folder from where I create the mp3's (I have to split
files, chop of long lead times/ exit times etc.) and move it to my
music folder USUALLY wmp sees the directory and adds an album called
'unknown'. I then edit the album to add it's name, who the musician is
etc. and USUALLY that works.

about 40% of the time however wmp only 'sees' SOME of the songs in the
folder. It will play the others if I click on them in windows
explorer, but it won't show them as part of the album in wmp.

Part of the 40% it sees SOME songs, then later it will show me two
copies of the album, one with some songs, some with others...

A small portion of the time it just does not detect the music at all,
so I cut the directory out of my music folder, paste it elsewhere,
then cut it from the elsewhere and paste it back...

How can I make wmp recognize there are new albums? This hit and miss
is very frustrating and there seems to be no rhyme or reason to it...