OK, so I’m no uber expert either but I have managed to solve this problem on my own site. The issue appears to be that 3.7.1 has a problem in that new folders made for a new month to store uploads in are being given the wrong file permissions. This means that although WP can make the folder and put things in it, it can’t subsequently read the contents of that folder. So, change the permissions of the folder and bingo! WP can read the contents again. However, the problem simply returns at the start of the next month. I didn’t have this problem until updating to 3.7.1 and it’s reappeared like clockwork with December’s new folder being built incorrectly, following my fixing of November’s. I managed to fix both folders by using an FTP client (I’m on Mac, so used Fetch – I think Filezilla is the fave PC option?) to locate the folder and set its permissions to the same as all the others. The permissions have a cute three digit code to make it simple for us non-techies – WP was setting the folder to have 664 I think, which doesn’t work properly. Changing it to 775 works great. To do this with Fetch as your FTP program, you just navigate to the folder in question and right-click to see file info. At the bottom of the window is lots of tick boxes (don’t mess with these) just add the 3 digit code in the box. I can’t speak for FileZilla I’m afraid, but others may know? If using FTP is scary, don’t panic – all you’re doing is viewing your web server’s folder/file setup, just as you can view your own computer’s setup. You need your FTP address, your username and password. The folders you’re looking are for are in wp-content/uploads/2013/ – all new month folders (mine are called 11, 12 etc) had incorrect permissions and required fixing.
