Recently, I faced an error while upgrading one of my WordPress blogs. I never encoutered such error in my other blog. After researching on this issue, I found it was a bug the blogs which were running on IIS.
If your WordPress blog is hosted on Windows server, you may receive the following error and it may prevent automatic WordPress upgrade:
Destination directory for file streaming does not exist or is not writable
To resolve this, you have following options:
 Manually install the Hotfix plugin. You can download it from the following URL:
 Add the following to your
wp-config.php. Remove it once you complete the upgrade:
define( ‘WP_TEMP_DIR’, ABSPATH . ‘wp-content/’ );