'Package "doctrine.common" is already registered as "Doctrine.Common"

Question

On a fresh flow install, that is after copying my existing site and launching "composer install" with sucess, when I execute the "flow" command, I obtain the following error:

PHP Fatal error:  Uncaught exception 'TYPO3\Flow\Package\Exception\InvalidPackag
eStateException' with message 'Package "doctrine.common" is already registered a
s "Doctrine.Common".' in C:\Development\my-cyme\Packages\Framework\TYPO3.Flow\Cl
asses\TYPO3\Flow\Package\PackageManager.php:723
Stack trace:
#0 C:\Development\my-cyme\Packages\Framework\TYPO3.Flow\Classes\TYPO3\Flow\Packa
ge\PackageManager.php(1061): TYPO3\Flow\Package\PackageManager->registerPackage(
Object(TYPO3\Flow\Package\Package), false)
#1 C:\Development\my-cyme\Packages\Framework\TYPO3.Flow\Classes\TYPO3\Flow\Packa
ge\PackageManager.php(881): TYPO3\Flow\Package\PackageManager->registerPackagesF
romConfiguration()
#2 C:\Development\my-cyme\Packages\Framework\TYPO3.Flow\Classes\TYPO3\Flow\Packa
ge\PackageManager.php(815): TYPO3\Flow\Package\PackageManager->scanAvailablePack
ages()
#3 C:\Development\my-cyme\Packages\Framework\TYPO3.Flow\Classes\TYPO3\Flow\Packa
ge\PackageManager.php(155): TYPO3\Flow\Package\PackageManager->loadPackageStates
()
#4 C:\Development\my-cyme\Pac in C:\Development\my-cyme\Packages\Framework\TYPO3
.Flow\Classes\TYPO3\Flow\Package\PackageManager.php on line 723

I'm really out of clue here on what to do or what's causing this issue. Nothing was found on the web either.

Answer 1

I had to delete the PackageStates.php file and then everything worked fine.

Answer 2

I’ve had this issue recently, too (and so did a colleague). Deleting Packages/Libraries/doctrine/common and running a composer install fixed the issue.