EMAIL USERS causing a loopback failure on WordPress

I can’t replicate this problem – Email Users works fine on the three web sites I have it installed on.

Well, it it helps, I have a similar problem. Activating the plug-in produces this warning: “The plugin generated 2 characters of unexpected output during activation. If you notice “ headers already sent ” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin.”

But, more worryingly, if I then run WP’s Health Check, I see (under ‘Critical Errors’) “Error: A plugin has prevented updates by disabling wp_version_check()”

De-activating the plug-in removes this message – but it would probably produce the ‘loop-back’ message the OP received.

Hmmm – that sounds suspicious because Email Users doesn’t disable the WordPress version check. I would do the following:

1. Temporarily disable all plugins and see if the issue persists. If it does when all plugins are disabled, it is likely a theme issue.
2. If the problem stops when all plugins are enabled, enable only Email Users and see if the problem comes back.
3. If the problem does return with only Email Users enabled, temporarily switch themes to one of the default WordPress themes (e.g. Twenty Ten, Twenty Twelve, etc.) and see if the problem persists. If it goes away, it is a theme issue.
4. If the problem does not return with only Email Users enabled, enable the other plugins one at a time until the problem comes back. If/when it comes back, the last plugin enabled is likely the conflicting plugin.

It is entirely possible that Email Users is the culprit but since the code hasn’t changed in a very long time, I would expect more reports if it is due to a WordPress change.

Thanks for the prompt reply. I am inclined to agree – if this was a general problem, you’d know about it by now. Looking at it a bit more closely, I think this error message is misleading – I think the version check is disabled, but it is very likely to do with some read/write permissions being mis-set. This – if it’s true – is my responsibility, not the plug-in’s! I will investigate.

Having said which, even with all other plug-ins disabled, I still get the “characters of unexpected output” message when re-activating the plug-in. That doesn’t seem to actually stop it activating, nor does it produce any ‘headers already sent’ messages, so I’m not too worried about it.

Thanks again for your help.

Well – just as an update to this: I put WP in Troubleshooting mode and enabled just one plug-in – Email Users. My error returned: “Error: A plugin has prevented updates by disabling wp_version_check()”. Then, whilst still in trouble-shooting mode, I tried two different themes, each time running the ‘Health Check’ afterwards. The error persisted. I came out of troubleshooting mode, swapped back to my original theme (twenty-ten) and disabled Email Users. Re-ran the health-check and the error is gone. I’m wondering if to try an earlier version of Email Users, if there is one in the repository. I know that’s not an ideal solution, so appreciate any alternative suggestions.

OK – well, I ‘solved’ this eventually. So, in case it helps anyone, here’s what I did. More in hope than expectation, and as all else had failed, I completely removed Email Users. When I say ‘completely’, I mean even to the extent of searching through the entire DB and removing any references to it. Then I re-installed with a fresh download, activated and – pffft! – all error messages gone.

HTH somebody.