CoolRunLT

Hey there!

I have had similar troubles in the past, but that does NOT mean you won’t have to use Jetpack, this can happen with almost any plugin.

Here is how I solved it over on my site at Sweet Life Fitness (in fact, the entire site wasn’t showing up and showing the “Cannot Modify Headers” problem – it was a mess!)

Here we go. First off, you need to know WHERE the issue is coming from. Let’s use your error as an example:

Warning: Cannot modify header information – headers already sent by (output started at /home/content/98/5590898/html/dcnet/wp-content/plugins/jetpack/class.jetpack-options.php:46) in /home/content/98/5590898/html/dcnet/wp-includes/pluggable.php on line 899

Now, the BOLDED section is the culprit. Not pluggable.php. So, what you have to do is go into your FTP (use a FTP host like Dreamweaver, FTP, FileZilla, etc. – if you don’t have one, you can also try to go into your FileManager with CPanel or whatever service your host runs on).

Step 1. Go into /home/content/98/5590898/html/dcnet/wp-content/plugins/jetpack/class.jetpack-options.php (or whatever the location is showing in the first set of parenthesis) Copy (CTRL-C) the entire document – no more, no less.

Step 2. Open NOTEPAD in Windows and PASTE (CTRL-V) the entire document into notepad. Go to the top of the file and make sure there is no extra space before <? php and at the end of the document make sure there is no extra space after ?>

Step 3. Save AS in Notepad. Rename the file to jetpack-options.php (the original file located in Step 1).

Step 4. Go into your FTP/File Manager, and upload the PHP file. It will probably ask you if you want to overwrite the file (because it already exists) – YES you do want to overwrite it (just make sure it matches the copy/paste you did in steps 1 and 2.

Step 5. Refresh your Browser, and the original error message *Should* go away.

But wait…there may be more!

Then, it might flash another error, instead of /home/content/98/5590898/html/dcnet/wp-content/plugins/jetpack/class.jetpack-options.php:46 as the culprit, it may throw something random like /wp-content/plugins/someplugin/theplugin.php. For example, the error would then show something like:

Warning: Cannot modify header information – headers already sent by (output started at /home/content/98/5590898/html/dcnet/wp-content/plugins/anotherplugin/anotherpluginexample.php:46) in /home/content/98/5590898/html/dcnet/wp-content/plugins/random.php on line 876

How to fix it? Follow steps 1-5, finding this new file under wp-content/plugins.

After that, YES – it may happen yet again. A new error code! This time it might even be pluggable.php, or wp-login. Regardless, just keep following steps 1-5 until it clears up. There was one time I had to do this for 9 or 10 times before it stopped showing all of the errors.

The key is finding whatever file is showing up first (in this example, in the bolded piece above) and doing Step 1-5.

I sure hope this helps. It may not work for everyone, but after trying all of the other help files with no luck, this was what worked for me. Even better yet, when I followed this 5 Step process, I have been 1 year of shenanigans free!!!

If you have any questions or need clarification, let me know.

Bob

Hey there!

I’m hoping to help YOU and everyone who has this bloody error once and for all. This worked for me, and I sure hope it works for you. I once had the issue happen on my site over at: SharpeFIT.com not once, but THREE times, and have safely recovered it after many head-bangs against the computer keyboard (lol).

(*Note: I’ve tried the whole <ob_flush> and removing “blank lines” from the other help files, and nothing worked at all – what I’m about to share was the only thing that worked for me*)

Here we go. First off, you need to know WHERE the issue is coming from. Let’s use your error as an example:

Warning: Cannot modify header information – headers already sent by (output started at /home/paulswanson22/travelerpaul.org/wp-content/themes/thesis_185/custom/custom_functions.php:1) in /home/paulswanson22/travelerpaul.org/wp-includes/pluggable.php on line 876

Now, the BOLDED section is the culprit. Not pluggable.php. So, what you have to do is go into your FTP (use a FTP host like Dreamweaver, FTP, etc. – if you don’t have one, you can also try to go into your FileManager with CPanel or whatever service your host runs on).

Step 1. Go into /wp-content/themes/thesis_185/custom/custom_functions.php (or whatever the location is showing in the first set of parenthesis) Copy (CTRL-C) the entire document – no more, no less.

Step 2. Open NOTEPAD in Windows and PASTE (CTRL-V) the entire document into notepad. Go to the top of the file and make sure there is no extra space before <? php and at the end of the document make sure there is no extra space after ?>

Step 3. Save AS in Notepad. Rename the file to custom_functions.php (the original file located in Step 1).

Step 4. Go into your FTP/File Manager, and upload the PHP file. It will probably ask you if you want to overwrite the file (because it already exists) – YES you do want to overwrite it (just make sure it matches the copy/paste you did in steps 1 and 2.

Step 5. Refresh your Browser, and the original error message *Should* go away.

But wait…there may be more!

Then, it might flash another error, instead of /wp-content/themes/thesis_185/custom/custom_functions.php as the culprit, it may throw something random like /wp-content/plugins/someplugin/theplugin.php. For example, the error would then show something like:

Warning: Cannot modify header information – headers already sent by (output started at /home/paulswanson22/travelerpaul.org/wp-content/plugins/someplugin/theplugin.php:48) in /home/paulswanson22/travelerpaul.org/wp-includes/random.php on line 876

How to fix it? Follow steps 1-5, finding this new file under wp-content/plugins.

After that, YES – it may happen yet again. A new error code! This time it might even be pluggable.php, or wp-login. Regardless, just keep following steps 1-5 until it clears up. There was one time I had to do this for 9 or 10 times before it stopped showing all of the errors.

The key is finding whatever file is showing up first (in this example, in the bolded piece above) and doing Step 1-5.

I sure hope this helps. It may not work for everyone, but after trying all of the other help files with no luck, this was what worked for me!

If you have any questions or need clarification, let me know.

Bob

Hey I figured this out today! It turns out to be a conflict with the CDN. If you go into your CDN file, click on “Host Theme Files” to ensure it is UNCHECKED. This is what was causing the issue. I assume it was something to do with a disagreement in minify & hosting on CDN.

All seems to be working great now in all browsers. Back to using W3TC and feeling great!

I hope this helps others who run into this issue.

My website is SharpeFIT hosted with W3TC and MaxCDN

Thanks

I’m having the same issue. When activated, my site loads fine in Chrome and IE explorers, but the stylesheet for the theme is missing in Firefox and other third-party browsers.

I deactivated the plugin and my style sheet shows up. I tried manual minify and tried adjusting setting and nothing works. Seemed to work fine with the prior version of W3TC, but this newest update is what is causing the problems.

Anyone know how to fix this? Is there a setting that is triggering this problem?

I’ll probably de-activate the plugin so I can keep my style sheet until I figure out what is causing the bug. Please check out browsershots to see what I mean – you’ll see some pics look great, and some have the stylesheet gone: https://browsershots.org/https://www.sharpefit.com/order-shakeology/

Site is: https://www.sharpefit.com

The new update was actually breaking my theme (making it show up bad in Firefox). I deactivated this plugin since it was doing it, and my Yslow score actually went up and my site works great now. I miss the original W3TC before this past update :-/

Having the same problem here with the latest release. Noticed a huge decrease in Y-Slow score (A to E). Not sure how to fix this one yet – my e-mail and setting in Cloud Flare are all 100% right.

Anyone find a way to make this work yet?

Yikes, there are a lot of concerns with this W3TC upgrade. Cloudflare is having a hard time communicating with the settings, and in MaxCDN it is asking for things like Consumer Secret which isn’t really found in my CDN. Not sure why W3TC didn’t adapt settings from the previous version, so I hope a new update comes out, because I can’t get anything to work like it was before ??

Ok, I must say that this was immensely appreciated and helpful! As a newer WordPress user, Andrew, you have provided some key points. Also, Alchymyth, no intentional spamming, this is one of my key sites that gets the most traffic, which is why I was excited about the speed boost.

I will definitely take your points seriously!

As for themes, I’d love to get some input from the community on their favorites. Is it best from most points to use the simple versions such as Twenty Twelve (Twenty Eleven) over the things like newslayer which is what is on my site now?

Good start, much better than when I started :-). I would check out your top image as it loaded slow on my machine. Make sure you check out your options to ensure the image is a good size. I also recommend a plugin called WP-SmushIT as it helps with keeping the images sized appropriately to help them load quick.

Nice screenshots! It always looks like the Twenty (Ten/Eleven/Twelve) themes are the most user friendly, and are super speedy in regards to page load time.

Thanks for sharing

Another quick question. I go into each file through FTP and double check white space, and there isn’t any. I save the file, and each time I refresh my admin screen after doing that, a new error pops-up. Now it mentions output with /plugin.php. Any reason for the consistent changes in error messages after save?

Warning: Cannot modify header information – headers already sent by (output started at /hermes/bosweb26d/b843/ipg.sharpefitcom/wp-includes/plugin.php:1) in /hermes/bosweb26d/b843/ipg.sharpefitcom/wp-login.php on line 349

Warning: Cannot modify header information – headers already sent by (output started at /hermes/bosweb26d/b843/ipg.sharpefitcom/wp-includes/plugin.php:1) in /hermes/bosweb26d/b843/ipg.sharpefitcom/wp-login.php on line 361

Would you also recommend removing the plugins from FTP all together or just renaming them for the time being until I find the culprit?

FTP is my only option since the admin section is completely dead at this point.

Thanks for your help. This will be very tricky as I have had the Admired Theme live for a few months now, and haven’t really changed anything (only have 3 plugins that haven’t been added recently or changed). From what I remember, there are no upgrades that I did in the last 48 hours if not longer.

It was weird as this just happened when I was just browsing my website randomly as a user (not even in the admin section). All of a sudden the page when blank (white), then decided to start showing the error messages all throughout.