unserialize(): Error at offset 0 of 40 bytes Error

Question

I Want to run my application in localhost with php artisan serve but I get this Error unserialize(): Error at offset 0 of 40 bytes where is my problem?

Answer 1

You have to set a news Key Generate because

php artisan key:generate 

After that test again to run the Laravel Application

php artisan serve 

Answer 2

I got the same error, when I upgrade a Laravel 5.5 app to 5.6. The error comes form the EncryptCookies-Middleware.

Delete the cookies in your browser and/or clear your session-files in your Laravel app.