Can’t Edit Theme in WordPress? 14 Possible Solutions for You!

Whether you are learning how to edit WordPress themes or putting your expertise into action, sometimes you’ll find that you can’t edit theme in WordPress. As far as issues go, this is a critical one. Because if you get errors while editing the theme, your website customization, styling, and other crucial changes will halt!

As themes are basically the foundations of a WordPress site, you must find out the issues, pinpoint the possible reasons, and fix them at once. Otherwise, your WordPress theme edit opportunities are simply wasted.

That’s where I come in!

I’ve categorized the general issue of “can’t edit theme in WordPress” into 4 separate segments — each with multiple solutions. As of now, I’ve listed a total of 14 solutions for you when you can’t edit WordPress theme files.

See which specific issue matches yours and fix them by following the given solution/steps. I hope this guide will help you edit your theme files in WordPress once again.

Issue #1: theme customizer stopped working/live preview not working

I hate it when this happens!

You know, you’re making a critical change to the appearance of your website and suddenly the live preview goes poof! Or worse, the customizer stops working altogether. This interruption is a common one, and annoying too — for all the right reasons.

But don’t worry, as every problem in this world has a solution — at least in WordPress! Whether the problem is with the WordPress customizer not working or the WordPress theme preview not working, there’s a multitude of possible reasons and a fix for each.

Possible reasons & fixes

The following are probably why (along with the solutions) you can’t edit theme in WordPress as the theme customizer live preview goes blank or the WordPress customiser not working properly:

1. Conflict with plugin(s)

Plugin conflict is the most common explanation behind the errors in the theme customizer’s functionalities or preview screen. The conflict can be the result of —

• installing a new plugin containing code that conflicts with your theme or the WordPress core
• updating an installed plugin (automatically/manually) that has bugs/issues in the updated version
• plugin leftovers left behind by a removed plugin

To resolve these plugin conflict issues with your theme, follow the below steps:

Step 1: Disable/deactivate all plugins on your WordPress website.
Step 2: Clear all your cache including plugin cache and server cache.
Step 3: Now, re-activate each of your plugins one by one to see which one is the culprit that recreates the issue you initially had with the customizer.
Step 4: You can contact both your theme and the buggy plugin’s vendor to get a solution from them. Also, you can just ditch that plugin altogether and get an alternative from the WordPress plugin repository.

2. “WordPress Address” and “Site Address” mismatch

As peculiar as it may sound, having a mismatch between the “WordPress Addresses (URL)” and the “Site Addresses (URL)” can lead to the customizer preview screen not loading entirely/properly. So, to be on the safe side, this problem should be nipped in the bud!

Here’s how you can easily solve this address mismatch issue:

• Step 1: From your WordPress dashboard, go to the “General Settings” (the first option under the Settings tab).
• Step 2: See if the “WordPress Address” and “Site Address” are both the same or not.
• Step 3: If they do mismatch as you suspected, see which one is correct or which one you prefer and replace the incorrect address with it.
• Step 4: Hit the “Save Changes” button and check if the problem with your theme customizer is still happening or not.

That’s it! Now that wasn’t too hard, was it? Sometimes simple fixes like this can go a long way!

3. Javascript blocked

Sometimes you may get bizarre errors on your theme customizer. This can range from the buttons not working on menu items on the customizer to even the disappearance of those items as a whole! Or, maybe the elements just don’t respond when clicked or dragged. And there’s always the issue of live preview not working.

The above issues are, almost always, the results of Javascript getting blocked. The Javascript codes can get blocked by one/multiple plugins or other existing scripts on the website.

To fix this issue, you can try —

• Finding if any plugin is conflicting with your theme and blocking scripts on the customizer
• Contact plugin/theme author’s support system to find a solution
• Clearing all available cache

4. Menu item(s) missing/invalid

Menu items go missing or get tagged as invalid when the page or the post linked to that item is deleted. Blocking issues like this can, at times, lead to WordPress theme customizer errors like preview screen not loading or edit options not working.

The solution to this problem is simple — locating and removing the invalid menu links. To do that, follow this procedure:

1. From your WordPress dashboard, navigate to “Appearance” → “Menus” tab.
2. Look for red-marked menu items, which usually indicate missing/invalid ones.
3. If there’s any red-marked menu item, click on the down arrow of the item to open an expanded list of options. After that, click “Remove”.
4. Click on the “Save Menu” button after you finish deleting all invalid items.

This quick and easy method will take care of the menu issue and hopefully fix your customizer at once.

5. Browser-related issues

“With great browsers come not-so-great issues and incompatibilities” is something Uncle Ben never told us, which he definitely should have! All popular web browsers (not spiderman though) and third-party browser extensions/add-ons can sometimes cause errors for your WordPress website, and the theme customizer is no different here.

Disabling add-ons

If you suspect that there’s an extension/add-on that’s causing the theme customizer to act funny and all other solutions don’t fix that, you might want to disable that. Every browser has its own specific way of disabling 3rd-party add-ons, so follow the guideline provided by your web browser’s documentation.

Browser cache issue

Taking no chance, consider clearing the cache of your browser too. Sometimes all it takes to resolve the theme customizer issues is this simple yet effective task.

Much like disabling extensions, the cache-clearing process varies from one web browser to another. While the procedure is pretty basic, you can search for how to do it on your browser beforehand.

6. Outdated WordPress environment

Also, you might actually be a victim of the good old “backdated WordPress” issue. The solution is simple: just update it! (but of course, by maintaining protective measures like testing on the staging site, ensuring a backup, etc).

Issue #2: theme edit option deactivated/disappeared

It’s not every day that you see some magic happen right in front of your eyes. Like when you realize that the theme edit option has vanished from your WordPress dashboard! Some magic, huh?

When you can’t even find the option, you must wonder how to edit WordPress theme for your website. But worry not!

Possible reasons & fixes

What to do when the WordPress customizer not showing on your dashboard? Has your WordPress appearance editor gone missing?

Try these in case of your WordPress theme editor missing —

1. Turning on the edit option

Sometimes, the reason is plain simple. Whether by mistake or willingly, you disabled the theme edit option either to minimize vulnerability or any other issue. To re-activate the option and edit WordPress theme files once again, follow the below steps:

Step 1: At first, go through all standard security and backup measures as you’ll be making sensitive changes to your site. The measures may include backing up your entire website.

Step 2: Check if any of your installed plugins have a theme edit enable/disable option. If the option is turned off, turn it on.

Step 3: If the above step didn’t resolve the issue, you’ll have to do some manual edits via the FTP client of your site. If you aren’t experienced/confident enough to make the changes yourself, consider opting for professional assistance. Then again, the procedure is rather simple, so you can do it yourself if you want.

Step 4: Now, access your files via the FTP client and search for the ‘wp-config.php’ file.

Step 5: Open the editor window directly on the FTP or download it for editing with your preferred tool for PHP code. If you’re unfamiliar with such tools and your FTP client doesn’t allow you to directly edit files on their system, you can download and install Visual Studio Code, Notepad++, or a similar code editor to edit the configuration file.

Step 6: Find the following line of code in the file —

define(‘DISALLOW_FILE_EDIT’, false);

Step 7: To turn the theme editing option on, replace the value ‘false’ with ‘true’ so that the line looks like this —

define(‘DISALLOW_FILE_EDIT’, true);

Step 8: Save the file on your server. If you made the changes by downloading the wp-config.php file, then replace it with the existing one on the server.

And voila! Now you can edit the theme on WordPress once again.

2. Restoring backup/re-installing theme

Alternatively, the disappearance of the theme edit option might simply be bugs in the theme files or the theme version being outdated. So, to repair it, you can —

• Update the theme of your website. Remember to create a backup beforehand. You can also use a child theme for this step to stay safe.
• If you have a backup of a previous version, you can consider rolling back if it solves the issue.

Issue #3: internal server error (500)

“500 internal server error” is a message everyone has stumbled upon while surfing the internet. It’s a server-side error and with networks & connectivity, it’s bound to happen. But when you get this error on your own website, that too after opening the appearance customizer…
Oh, the horror!

But rest assured — this 500 error can easily be fixed so that you can edit your website’s appearance using the theme customizer.

Possible reasons & fixes

Here are the most likely causes behind the 500 internal server errors on the theme customizer, along with their respective fixes:

1. Exceeding memory limit

The error on the customizer window can simply be the lack of available memory. This server resource overload could result from resource-heavy third-party plugins or junk code.

While it’s essential to take care of resource waste, a more straightforward fix would be to increase the PHP memory limit on WordPress.

Learn how to increase your WordPress memory limit from this resourceful blog post from Wpmet.

2. Outdated version of PHP

In addition to the PHP memory limit issue, this error screen could also be the result of having an outdated version of PHP on your WordPress website.

It’s always considered good practice to keep the PHP version up to date on WordPress sites. The reasons behind it are —

• The latest PHP version ensures a faster and more optimized speed
• It also protects you from security threats and vulnerabilities

How to update PHP in WordPress, you ask? Simply go to this list, find your hosting provider, and read the linked guide. If your hosting provider is not listed there, then contact them and ask how to do it for your WordPress website.

3. PHP processing error

If you can’t edit theme in WordPress and constantly receive the internal server error, there’s a possibility that your website is facing errors while processing PHP codes. To check if that’s the case, you’ll need to access the PHP error logs.

There are multiple ways of checking the logs. The two most common methods include —

• installing a log viewer/monitoring plugin for WordPress
• accessing the ‘debug.log’ file inside the ‘wp-content’ folder using your preferred FTP client

If you do find any error in the logs, you can —

• fix the issues yourself given that you have expertise/experience
• seek professional help to debug
• contact your hosting provider for some assistance

Issue #4: CSS styling changes aren’t working

It’s irritating when you start editing the stylesheets or adding your own custom CSS, but you realize the changes aren’t taking place on the theme customizer. As a result, you fail to make styling changes to your website, which is quite a red flag!

Let’s dig deeper and find out why it happens.

Possible reasons & fixes

1. CSS caching issue

Whether by a caching plugin or some other reason, you might be a victim of caching the CSS of your website. Sometimes these caches conflicts with the CSS changes you make through the theme’s customizer. As a result, you’ll have a hard time editing CSS in WordPress theme of your website.

All you have to do is disable the caching plugin or turn off whatever’s causing the CSS codes to be cached. That way, you’ll be sure if this is the actual issue or not.

2. Concatenated script

WordPress combines all scripts into one concatenated script at runtime, including Javascript and CSS. There’s a possibility this concatenation may result in theme customizer CSS changes not working or even the whole WordPress dashboard acting strange!

Well, here’s the solution:

Step 1: Open the ‘wp-config.php’ file using the FTP client for your WordPress site.
Step 2: Just above the comment that says something along the lines of “That’s all, stop editing! Happy blogging/publishing”, add this code:

define( 'CONCATENATE_SCRIPTS', false );

What this line of code does is that it commands WordPress to stop combining/concatenating Javascript, CSS, and other forms of scripts together.
It’ll look something like this after adding the line of code:

Step 3: Save the file and check if the problem is resolved or not. In order to revert to the default settings of script concatenation, change the ‘false’ value of the above code into ‘true’ or simply remove the line.

Closing notes

There you have it! I’ve listed down not just all possible theme customizer edit errors, but also the possible solutions for them. I hope your issues will be resolved via any of these 14 solutions.

Feel free to comment below if you have any suggestions/queries regarding the above discussion, as well as any new issue/solution for me to add to this guide. I’ll be more than happy to discuss them.