Magento 2: RuntimeException it is being used by another process

Question

When I do clear cache using command line & refresh page on Frontend 1st time it gives below exception.

1 exception(s): Exception #0 (RuntimeException): The path "D:/wamp/www/magento2/var/generation/Magento/Checkout/Model/Session/Interceptor.php.6260" cannot be renamed into "D:/wamp/www/magento2/var/generation/Magento/Checkout/Model/Session/Interceptor.php" Warning!rename(D:/wamp/www/magento2/var/generation/Magento/Checkout/Model/Session/Interceptor.php.6260,D:/wamp/www/magento2/var/generation/Magento/Checkout/Model/Session/Interceptor.php): The process cannot access the file because it is being used by another process. (code: 32)

When i refresh same page again/2nd time it loads page proper. What will be cause for above exception?

Answer 1

My best guess is that while the setup:di:compile compilation process is running and Magento is processing requests (e.g. tries to bootstrap), this exception might appear.

Suggestion:

• enable maintenance mode
• stop cron processing
• deploy your changes (run compilation, static content deploy, etc)

From my perspective this is not a bug, but imperfect deploy process.

I will try to update the answer if I found out any more details.

Answer 2

Improper deployment process leads to this kind of error, just remove all the files from var/generation folder and run a setup:upgrade command, this issue must be resolved after this.This works for me.