3.5 on IIS7 unable to update plug-ins and themes

Does it prompt for FTP credentials?

Did you upgrade to 3.5 via FTP manually, or via the auto-upgrader?

Alright, this sounds like it’s caused by some changes made in http://core.trac.wordpress.org/ticket/20778

Specifically, this means that one of the temporary directories reported by PHP is unwritable by the IUSER account, or PHP is mis-reporting being able to create files in one of the temporary directories

Would you be able to do a little bit of debugging for me?
If you install this plugin (by FTP) and either paste the output here (If you’re happy letting the world know the file paths) or emailing the output directly to me at [email removed, see later posts], I’ll be able to work out if there’s a core bug, or if it’s just a server configuration issue.
The plugin: http://dd32.id.au/files/test-temp-dir.zip

(The plugin creates a top level menu called ‘Test Plugin’ )

The problem thats happened here, is that the is_writable() function in PHP has a few bugs, and doesn’t report correctly in some windows environments.

We changed to using a special function – win_is_writable() which attempts to create a file in the directory in order to determine if a folder is writable, unfortunately, we didn’t update it in all the locations the is_writable() function was used.

As a result of this, WordPress now attempts to use the Windows Temporary directory which, while already writable by PHP, is_writable() says isn’t (because it checks a different ACL flag than the filesystem actually uses).

Finally, this renders WordPress updates & plugin/theme installs unusable.. an unfortunate side effect no one who had tested WordPress on windows had run into (apparently no-one who used the beta’s or RC’s had a IIS7 with limited write access to the Temp directories, and although I had tested IIS myself, I had temporary directory permissions set differently).

This issue is being tracked in http://core.trac.wordpress.org/ticket/22900

I hope someone who has been affected this will join the fun and test out WordPress 3.6 betas & Release Candidates next time, so that we’ll get better tester coverage and hopefully never run into a similar issue again.

As a work around, if you don’t want to enable PHP write access to your temporary directory, you can add this to your wp-config.php file:
define( 'WP_TEMP_DIR', ABSPATH . 'wp-content/' );

(IIS7) Added Modify/Write permissions to the C:\Windows\Temp folder for IIS_IUSR but this didn’t seem work. Do I need to restart the server or anything else?

For now I’m using the define( ‘WP_TEMP_DIR’, ABSPATH . ‘wp-content/’ ); workaround.

Just installed WP 3.5 and got the same error. As indicated in earlier posts, the issue is related to the IUSR account not having access to the Windows\Temp folder. However, after some testing, I found that the user does not need write access. In my case, I have the defaults (Read & Exec, List Folder Contents, Read) set and it works fine. I tested this by then removing the user and it failed again. So, just adding the IUSR to the folder will suffice. Looking fwd to 3.5.1 to get rid of this security hole…

Here’s an example of the error you can expect to receive:

Downloading update from http://downloads.wordpress.org/plugin/%5Bplugin name here]…

Warning: touch() [function.touch]: Utime failed: No such file or directory in C:\websites\clients-a\astolfo\www.plastibots.com\wordpress\wp-admin\includes\file.php on line 179
Unpacking the update…

The package could not be installed. PCLZIP_ERR_MISSING_FILE (-4) : Missing archive file ‘C:\WINDOWS\TEMP/[plugin name here].tmp’

I can confirm I’ve seen this also on Windows Server 2003 and IIS6. The workaround of the define in wp-config.php also works.

I am getting this error message the solution above doesn’t work… I am running Linux cPanel so it would be good that this is fixed in a update as I have 50 sites and I don’t want to be hard coding all the sites. Remember there are lots of novices who don’t know how to code and they’ll not be able to upload images…