How to resolve Download failed : Destination directory for file streaming does not exist or is not writeable in WordPress
After some digging I was able to pin down what was the issue with my WordPress installation that was causing the error message mentioned above.
It turns out I am hosting WordPress on a Windows Box and therefore PHP uses a temporary directory to which it may not write.
To resolve this there are two possible approaches:
Give your application pool access to that temporary folder so you can extract the updates there
Tell WordPress to use a different Temporary folder
Option two is generally the easiest one specially when you don’t have access to the Windows Host.
In order to accomplish this simply follow the instructions below:
Add this line of code anywhere in the root file wp-config.php:
/* Setup a temporary folder for uploading and updating WordPress */ define( 'WP_TEMP_DIR', ABSPATH . 'wp-content/temp/') ;
and create a new folder named “temp” inside: /wp-content/
In case you were wondering php uses the C:WindowsTemp folder by default generally.
That is all, I hope this helps!