Users complaining of receiving duplicate emails

[cscgal]

Some members on my site are complaining that they sometimes receive duplicates of forum emails. One member says it's been happening for a couple of weeks, which would line up to when I upgraded to vB 3.5, while another member says it has only been happening for the past week. (I think that the person who said a couple of weeks is probably mistaken, because a bunch of members all brought it to my attention at once just this week.)

I have always used the vB mailqueue, even with vB 3.0. I tried both enabling and disabling the with locking option but it didn't seem to resolve the issue.

Here is the thread on my site where all of my members explain the problem:
http://www.daniweb.com/techtalkforums/thread46082.html

I did make a change to class_mail.php.

I replaced:

            $headers .= 'Content-Type: text/plain' . iif($encoding, "; charset=\"$encoding\"") . $delimiter; 

with

        if (THIS_SCRIPT=='newsletter')
        {
            $headers .= 'Content-Type: text/html' . iif($encoding, "; charset=\"$encoding\"") . $delimiter;
        }
        else 
        {
            $headers .= 'Content-Type: text/plain' . iif($encoding, "; charset=\"$encoding\"") . $delimiter;
        } 

Other than that, I have one other file hack that does stuff with bbcode and then just plugins. All of my vB 3.5 plugins are custom written so I know everything that's there, and nothing has anything to do with vB mail or scheduled tasks or anything like that. (Mostly my SEO mod_rewrite hack).

Any ideas??

[Steve Machol]

This is most likely a server issue but if you want to remove vB from the list of suspects, remove any hacks and disable your plugins, then see if you still have this problem.

If so, reupload all the original vB non-image files (except install.php). Make sure you upload these in ASCII format and overwrite the ones on the server.