Posted by Rob
Posted on 10-31-2008 under Development

The fix for the I/O error might not be a permissions issue after all!

In honor of Halloween, I’m posting one of the most frightening things you can possibly imagine….a Cryptic Wordpress Error Message!  Of Doom!  Muwhahahahahah! (As an added bonus, in honor of Halloween, I have peppered this post with some scary adjectives!)

Ahem!  Okay.  It’s no secret that different web servers are set up horrifically different.  Unfortunately for developers of large web software packages (like the ghoulish folks over at Wordpress.org, or Drupal), this can mean having to account for a lot of different possible variables, and occasionally things slip through the cracks (and fester!).

Unfortunately, one of those things has to do with uploading files using the Wordpress Flash Uploader, which is better than it used to be, but still prone to its share of wicked errors.

One of the most frustrating of all is the dreaded, mysterious, cryptic “IO Error”

There are a few different reasons for this error to occur.  If a non-scientific survey of Google search returns is anything to go by, the most common reason is a horrifying Apache permissions issue on your server.  The /uploads folder in /wp-content needs more lax permissions than the rest of your site generally in order to allow the Wordpress software to place images in there.  What permissions, exactly, differ from server to server.  If you need a good explanation of permissions and changing them (chmod), there are lots of good tutorials out there explaining it, such as this one.

Gruesome permissions, alas, aren’t the only cause of the dreaded IO Error.  In fact, there is another cause, one so easy to fix an undead zombie could fix it.  And I’m talking the slow moving kind of zombie who is missing a limb or a face-half.  If you are getting this error, go to the Wordpress backend, and try navigate over to your Settings tab, and then click on Miscellaneous.  Under Uploading, the first option, look at your uploads path (”Store uploads in this folder”).  If your path starts with a slash, which in the normal web world would be the correct way to notate a relative path of this kind denote the path to the /wp-content folder in relation to the root hostname, Wordpress will probably flip out.

The result, depending on your server, may be the spooky IO Error.  Sometimes the error will also be accompanied by the utterly useless message, “An error occurred in the upload.  Please try again later.” Gee, thanks Wordpress!

Again, depending on your slithering server setup (Halloween alliteration!), you may also get a slightly more useful error message:

The fix to is is to simply murder the preceding slash, so your path looks like this:

wp-content/uploads

Anyway, I hope this helps!  Happy Halloween!