Recently, I moved a WordPress site from one host to another. It was a fairly small site with a handful of plugins, but I wanted to make sure that everything was up-to-date after moving the site. First things first, I ran plugin updates, but that’s where I ran into this issue:
The update cannot be installed because we will be unable to copy some files. This is usually due to inconsistent file permissions.: wp-admin/includes/update-core.php
Installation Failed
Ugh.
Turns out, I needed to change my file and folder permissions to get the updates to complete successfully.
TL;DR
Folders need to be set to 775 and files to 664.
Using the Command Line
If you have command line access, you can also run the following commands:
Folders to 775
find /path/to/site/ -type d -exec chmod 775 {} \;
Files to 664
find /path/to/site/ -type f -exec chmod 664 {} \;
Bonus
You may also need to reset the group to the wordpress group or something that makes sense for you.
chgrp -R wordpress /path/to/site/
Once you do that, you should have no problem updating your WordPress plugins!