Missing appmanifest files? Games go missing?

[Pilsnerd]

Sometimes my app manifest files go blank. Steam will think the game isn't installed.
Adding/removing the library does nothing.
You cannot verify uninstalled games.
If my disk is full steam complains about not having enough free space so it won't even look to see if the files are already there. Sometimes I don't have the luxury of freeing up 80GB or so. The only problem I can find with anything is the game's appmanifest file is empty. Why is this happening? What is a quick way to fix this?
Getting tired of being my own IT guy. Getting older sucks.

[cinedine]

The appmanifest holds the information about what games are stored where and in which version.
Try to find out why it gets deleted or emptied. Usually it's a sign of Steam not closing properly.
Make a back-up of the file after each install, uninstall and update.

[hjgrfjhdjvhjzcv]

maybe