Some small Composer commands that might solve your problems: I’ve taken them directly from Jordi Boggiano’s (Composer co-creator) “In Depth Composer” talk at laracon 2013, so they should definitly do the job. Update Composer itself

composer self-update

Run a diagnostic

composer diagnose

Update your dependencies (note: The -v is the verbose parameter which shows additional info)

composer update -v

If still problems: reinstall the dependencies. Remove the vendor folder (manually) or via rm command (if you are in the project folder, sure) on linux before:

rm -rf vendor/
composer update -v

If it’s still not working, Jordi Boggiano recommends you to send a full bug report (containg full debug output, make it with -vvv) to the Composer crew.