Unable to fix corrupted Cornerstone installation

Long story short: I have a wordpress page running on X. For some reason, the Cornerstone plug-in associated with this X cannot update past version 1.24. As the license to this X install is lost, I have now purchased a new license for Cornerstone as a stand-alone plug-in. However, I cannot install Cornerstone as I cannot delete the fauly cornerstone plugin - I can only disable it.

How am I to proceed, in order to have an update Cornerstone plug-in?

Hi There @AwesomeX

Thanks for writing in! You don’t have to purchase Cornerstone plugin separately as it will be shipped with X theme.

To resolve your issue, first you need to check your X theme version as well. If you’re using an older version of X theme, you may have incompatibility issues and your automatic updates will not work correctly. You can see the latest X theme and it’s compatible version information from here (https://theme.co/apex/forum/t/troubleshooting-version-compatibility/195) and then update your X theme accordingly (https://theme.co/apex/forum/t/setup-updating-your-themes-and-plugins/62).

Once you update your X theme to the latest version, you can simply disable and delete your Cornerstone plugin, then head over to X -> Validation section and wait for few seconds to install the latest version of Cornerstone plugin automatically.

If this automatic installation did not work, you can also find the Cornerstone.zip plugin file under your X theme. Simply unzip X.zip file and locate Cornerstone plugin under (x/framework/cornerstone.zip), use it to install it as a normal plugin in your WordPress -> Plugins area.


Hi mldarshana,

Thanks for replying. I am aware that the Cornerstone plug-in ships with the X theme. That is how it was installed back in 2016, when an emplyee was designing the website in question. However, since then the Apex login credentials or any code associated with that purchase has long been lost. Thus, while I have X, I have no way of validating it or seek forum support for it. Despite this, will it still be possible for me to do as you advise, and update X completely, then disable and delete cornerstone and then re-install it?

As the problem is essentially that I cannot update the cornerstone plug-in, I thought I would re-install it (as it gives an error of some lack of file permissions). To re-install Cornerstone, I purchased a new Cornerstone plug-in license. However, to install this new Cornerstone plug-in, I must delete the old version. But, this is impossible. Or, at least I do not know how to do it.

Hey Jakob,

Please first uninstall Cornerstone and update X to the latest version. That is assuming your site’s still validated. After X is update to the latest version, X will redirect to X > Validation and going to that page will automatically install the latest compatible version of Cornerstone.

If you’re sites still validated also, you can get the license from the database. It’s in the wp_options table and search for x_product_validation_key as option_name. If you’re not familiar with MySQL, please ask your web host if they could get it for you.

If you can’t update X, regretfully, you’ll need to purchase an X license to update it. Then, the process I said above will apply. The Standalone Cornerstone license won’t help in this case because you first need to update X.


Hi Christian,

Sorry for the late reply. I appreciate your input, but I still cannot uninstall Cornerstone. I can only Deactivate it. On trying to uninstall Cornerstone, I get the error: Unable to fully remove the plugin: cornerstone/cornerstone.php

Thanks for the info on the product key, I will try and look for it.

Hi Jakob,

To uninstall cornerstone, you may login to your FTP then navigate to wp-contents/plugins and delete the cornerstone folder.

Another way is to login to your cpanel and navigate to file manager > wp-contents/plugins then delete cornerstone folder.

Hope this helps

Hi Paul,

Thank a lot, I did try to delete the plugin via FileZilla, but even this is unsuccessful. The plugin is located at: www/wp-content/plugins/cornerstone on my FTP. Attempting to delete it results in the error message: “550 Remove directory operation failed.” and “250 Directory successfullt chnged”.

Zero files are deleted. Do you have any additional advice?

Hey Jakob,

Just to get back to your original issue, depending on the version of X that is active on your site, it will automatically install Cornerstone as soon as you login to the Wordpress dashboard.

Also, since your site has X active on it, you will not able able to use the Cornerstone license to validate X. You will have to use another theme and validate Cornerstone using the license that you have.

At this point, what you can do is to download the latest version of Cornerstone from your Apex dashboard.

Once downloaded, unzip the file and you should have a cornerstone folder which the plugin files in it. Login to FTP and go to wp-content/plugins then delete the current cornerstone directory that is in there. Once deleted, upload the unzip cornerstone directory that you have just downloaded from apex.

Once all files are uploaded, go back to the Wordpress admin and you should have the latest version of Cornerstone on your site.

Hope this helps.

Hi Jade,

Thanks for your input. I realize that the X theme will auto-install Cornerstone. My attempt to delete the Cornerstone folder has been made without an open browser. I get that I can do a manual install of cornerstone - but I cannot do this as I cannot delete the original Cornerstone folder, and thus cannot make a new install.

So, I cannot install cornerstone manually nor automatically, because there is an existing folder named “cornerstone” in my plugins folder. As I cannot delete this folder, how am I to proceed?

Maybe I am missing something, but it seems somewhat paradoxical


I have no clue as to how, but after trying to delete the folder “wp-content/plugins/cornerstone” unsuccessfully, the cornerstone plugin was able to auto-update!

Hi Jakob,

In this case, please rename the wp-content/plugins/cornerstone to wp-content/plugins/cornerstone.old.

After that re-visit the validation page, Cornerstone plugin will be auto-installed.

Let us know how it goes!

Thanks for the assistance to all of you. For some reason, after fiddeling unsuccessfully on the FTP server, I was able to update the Cornerstone plugin. Everything else is updated as well now, and it all seems to be working flawlessly.

I do think the last fix with renaming the folders would have done the trick, if it had not spontaneously fixed itself. Probably, the corrupted file preventing auto-update was erased from the FTP server, as the first attempt to delete the folder did successfully remove 2 files.

The info from @christian_y about finding the registration key from MySQL was excellent - thanks a lot. I found the key but unfortunately it is already registered and thus I cannot add it to my account. Probably the old emplyee made an account and subsequently forgot about it. My question is then this: Is it possible to transfer this license to me? I assume the account it is registered to has been inactive for years, and if you have retained billing, the company will be the owner of the credit card used for the purchase.

Hey Jakob,

Please post the License in a Secure Note and I’ll forward it to our accounts manager.


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