Magento – Magento 2 – ‘ I can’t upload images on the store’ gives error “wysiwyg is not under storage root path”

So after a day of diving into this issue; disabling modules, enabling modules, removing changes in local etc etc, I found the problem.

I used an extension called PhPro_Translate to do a large amount of translations for front and backend from English to Swedish and so in my std install I have just inserted all the rows of translations into core_translate (as the extension does). It turns out that one of the 80 or so translated strings under the Mage_Cms module cause the error. I honestly did not have the energy to look into exactly which string as I still have 3400 rows working :), but I have a vague idea it could have been a Swedish word with umlauts.

In the very unlikely event that someone else runs into the same problem, that's the answer!

Cheerio

UPDATE: Since this could have implications in other contexts, here's what caused the js error. In one of the translations I had used single quotes around a word to denote it was the original English term but I had forgotten to escape the quotes. Voilà!

Create the new module, Then add below code in your module di.xml

/app/code/Vendor/Mymodule/etc/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="Magento\Framework\App\Filesystem\DirectoryResolver"
                type="Vendor\Mymodule\App\Filesystem\DirectoryResolver"/>
</config>

Now Create the file,

Vendor\Mymodule\App\Filesystem\DirectoryResolver.php

and add below code in the file:

<?php


namespace Vendor\Mymodule\App\Filesystem\DirectoryResolver;

use Magento\Framework\App\Filesystem\DirectoryList;

/**
 * Magento directories resolver.
 */
class DirectoryResolver 
{
    /**
     * @var DirectoryList
     */
    private $directoryList;

    /**
     * @param DirectoryList $directoryList
     */
    public function __construct(DirectoryList $directoryList)
    {
        $this->directoryList = $directoryList;
    }

    /**
     * Validate path.
     *
     * Gets real path for directory provided in parameters and compares it with specified root directory.
     * Will return TRUE if real path of provided value contains root directory path and FALSE if not.
     * Throws the \Magento\Framework\Exception\FileSystemException in case when directory path is absent
     * in Directories configuration.
     *
     * @param string $path
     * @param string $directoryConfig
     * @return bool
     * @throws \Magento\Framework\Exception\FileSystemException
     */
    public function validatePath($path, $directoryConfig = DirectoryList::MEDIA)
    {
        $realPath = realpath($path);
        /**
         * Since media directory is a symlink, need to run both paths through realpath in order for the comparison to
         * work.
         * The proper fix for this should involve a STORE > Configuration setting where an admin can choose whether to
         * allow symlinked directories.
         */
        $root = realpath($this->directoryList->getPath($directoryConfig));
        // END EDIT

        return strpos($realPath, $root) === 0;
    }
}

Please create the require file for module registration.php and module.xml