Where are my songs that were in the iCloud?

The edit from my post above:

You can check, if your iCloud GarageBand projects are still there, when you open your User Library in your Home folder.

~/Library/Mobile Documents/F3LWYJ7GM7~com~apple~mobilegarageband/Documents/

In the Library is a folder "Mobile Documents", and inside the folders to sync your apps with iCloud. Look for a folder with some weird name ending in mobilegarageband. Inside should be your projects.

You user library may still be hidden, as is the default in Mavericks: To open your hidden user library:

• Select the "Home" folder icon (the little house) in the Finder's sidebar and press the key combination ⌘J to open the "view options".
• Enable "Show Library Folder".
• Then open the Home folder and open the Library folder inside and navigate to ~/Library/Mobile Documents

And the second thing to check - is iCloud still enabled for GarageBand?

• Check your "System Preferences > iCloud" panel.
• Scroll down to "Docoments and Data" and click the "Options" button.
• Make sure, the checkmark besides GarageBand is active in the list of apps.

Is your GarageBand version still GarageBand '11 as in your signature?

Try TimeMachine.

With the F3LWYJ7GM7~com~apple~garageband10 folder open as the frontmost Finder window, enter Time Machine:

Then go back in time, until you find your projects.

We need to know more. What did you do between yesterday, when the songs still were there and today? Did they vanish right after the "OS X Mavericks (10.9.3)" update?

You can check, if your iCloud GarageBAnd projects are still there, when you open your User Library in your Home folder.

~/Library/Mobile Documents/F3LWYJ7GM7~com~apple~mobilegarageband/Documents/

In the Library is a folder "Mobile Documents", and inside the folders to sync your apps with iCloud. Look for a folder with some weird name ending in mobilegarageband. Inside should be your projects.

My version is actually 10.0.2.

Then check the folder ~/Library/Mobile Documents/F3LWYJ7GM7~com~apple~garageband10/

If the projects are gone, check your iCloud settings, if you are signed in with the same AppleID as previously.

If necessary, try to restore the com~apple~garageband10 folder with the projects from your backup.

You're welcome 🙂