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How to migrate a standalone WordPress site into an existing multisite network?

So, you’ve got a standalone WordPress site humming along nicely, and you’re thinking about folding it into an existing WordPress multisite network. The short answer? Yes, it’s totally doable, but it needs a bit of planning and careful execution. It’s not a one-click magic solution, so set aside some time and be ready to get into the details.

Why Migrate to Multisite?

Before we dive into the nitty-gritty of how, let’s just quickly touch on why you might even consider this. Multisite can be fantastic for managing several related sites under one WordPress installation. Think of it as a central hub where you can control users, plugins, themes, and updates for multiple websites. This can be great for agencies, businesses with many sub-brands, or even personal projects where you want to keep things neatly organized. It reduces the overhead of managing individual WordPress installations, making updates and security a bit more streamlined.

If you’re looking to migrate a standalone WordPress site into an existing multisite network, you may find it helpful to read a related article that provides insights on the process and best practices. This article offers step-by-step guidance and tips to ensure a smooth transition. For more information, you can check out the article here: How to Migrate a Standalone WordPress Site into a Multisite Network.

Initial Preparations: Before You Touch Anything

This is arguably the most crucial phase. Rushing here will only lead to headaches later. Think of this as getting your ducks in a row.

Back Up Everything

Yes, everything. Your standalone site’s database, files, themes, plugins – the lot. And then back it up again. Seriously, having a reliable backup is your safety net if something goes sideways. You can use a plugin like UpdraftPlus or contact your hosting provider for their backup solutions. For a full manual backup, you’ll need access to your site’s files via FTP/SFTP and your database via phpMyAdmin or a similar tool.

Understand Your Multisite Setup

Is your existing multisite a subdomain (e.g., site1.maindomain.com, site2.maindomain.com) or a subdirectory (e.g., maindomain.com/site1, maindomain.com/site2) setup? This distinction is critical because it impacts how you configure your new site’s URL and settings. Mixing these up can cause routing issues. Also, make sure you have admin access to the multisite network.

Clean Up Your Standalone Site

Before moving, take a moment to declutter. Delete unused themes, inactive plugins, draft posts you’ll never publish, and comments you’ve marked as spam. A leaner site is easier to migrate and will perform better once it’s part of the network. This also helps reduce potential conflicts with the multisite environment.

Check for Plugin Compatibility

Not all plugins play nice with multisite. Some are specifically designed for it, others work fine, and some will flat-out break. Review the plugins on your standalone site. For any critical plugins, do a quick search: “\[Plugin Name] multisite compatibility” to see if there are known issues or specific setup instructions for multisite. You might have to find alternatives for some.

The Migration Process: Step-by-Step

Alright, let’s get into the actual migration. We’ll break this down into several steps.

Exporting Content from Your Standalone Site

WordPress has a built-in export tool that’s quite handy for moving content.

Using the WordPress Export Tool
  1. Log in to your standalone WordPress site’s dashboard.
  2. Navigate to Tools > Export.
  3. Choose what you want to export. For a complete site migration, you’ll generally select “All content.” This will include posts, pages, comments, custom fields, terms, navigation menus, and custom posts.
  4. Click “Download Export File.” This will give you an XML file. Keep this file safe.

This content export gets your posts and pages, but it doesn’t move images, settings, or theme/plugin configurations. We’ll deal with those separately.

Setting Up the New Site on Your Multisite Network

Now, you need a placeholder for your old site within the multisite network.

Adding a New Site via Network Admin
  1. Log in to your multisite network’s dashboard as a Network Administrator.
  2. Navigate to My Sites > Network Admin > Sites.
  3. Click “Add New.”
  4. Site Address (URL): This is where understanding your multisite setup (subdomain vs. subdirectory) is crucial.
  • Subdomain: Enter the desired subdomain (e.g., myoldsite if your new URL will be myoldsite.maindomain.com).
  • Subdirectory: Enter the desired subdirectory (e.g., myoldsite if your new URL will be maindomain.com/myoldsite).
  1. Site Title: Give it a title that makes sense. You can change this later.
  2. Admin Email: Enter an email address for the site’s administrator.
  3. Click “Add Site.”

This creates the basic structure for your new site within the multisite.

Importing Content to the New Multisite Subsite

With your new site created, it’s time to bring in the content you exported earlier.

Using the WordPress Import Tool
  1. **Log in to the dashboard of your *newly created subsite (not the network admin, but the specific subsite you just made).
  2. Navigate to Tools > Import.
  3. You’ll see “WordPress” listed there. If you haven’t used it before, click “Install Now” underneath it.
  4. Once installed, click “Run Importer.”
  5. Choose the XML file you downloaded from your standalone site.
  6. Click “Upload file and import.”
  7. On the next screen:
  • You’ll likely be asked to assign authors. You can either assign existing users on the multisite or create new ones. Often, it’s easiest to assign all imported posts to an existing administrator on the subsite for now.
  • Crucially, check the box that says “Download and import file attachments.” This will attempt to pull the images and other media from your old site’s server into your new site’s media library. This is vital unless you plan to manually move them.

This process can take some time, especially if you have a lot of content and images. Be patient.

Moving Media Files

The WordPress importer tries its best, but sometimes it misses things, or your old site might have protection that prevents direct downloading. It’s often safer and more reliable to move media files manually.

Manual Media File Migration
  1. **Connect to your standalone site via FTP/SFTP.**
  2. Navigate to the wp-content/uploads directory. This is where all your images and media files are stored, usually organized by year and month.
  3. Download this entire uploads directory to your local computer. This might be a large download, so ensure you have enough space and a stable connection.
  4. **Connect to your multisite network’s root directory via FTP/SFTP.**
  5. Navigate to wp-content/uploads/sites/, and then into the directory corresponding to your new subsite’s ID. (Each subsite in a multisite network has a unique numerical ID, usually found in the wp_blogs table in the database or by looking at the URL when you’re editing the site in the network admin, e.g., wp-admin/network/site-info.php?id=MY_SITE_ID).
  6. Upload the uploads folder you downloaded from your standalone site into this subsite-specific uploads directory. You’ll likely want to merge/overwrite existing files if prompted.

After this, your media files should be accessible within the new subsite. The XML import should have updated the references in the database to point to these new locations.

Post-Migration Adjustments

You’re not quite done yet. Now it’s time to clean up and ensure everything is working as expected.

Permalinks and Settings

Your migrated content needs its links to work correctly.

Update Permalinks
  1. **Log in to the dashboard of your newly migrated subsite.**
  2. Go to Settings > Permalinks.
  3. Select your preferred permalink structure (it’s usually best to match what your old standalone site used).
  4. Click “Save Changes.” Even if it looks correct, doing this forces WordPress to flush and update its rewrite rules, which can resolve “404 Not Found” errors for your migrated posts and pages.
Review Other Site Settings

Go through Settings > General, Settings > Reading, etc., on your new subsite. Many of these settings won’t be brought over by the XML import and will revert to multisite defaults. Adjust the site title, tagline, email addresses, and other configurations to match your original standalone site.

Theme and Plugin Setup

This is where things can get a bit more hands-on.

Reinstall and Configure Themes

The XML export does not move your theme files or settings.

  1. Install your theme on the multisite network. If it’s a premium theme, you’ll need the license key. This is usually done by going to My Sites > Network Admin > Themes and “Add New,” then activating it for your specific subsite.
  2. Activate the theme on your new subsite (Appearance > Themes).
  3. Reconfigure theme options. Most themes have a customizer or theme options panel where you set up logos, colors, fonts, layouts, etc. You will need to manually re-enter these settings on your new subsite to match your old site. Unfortunately, there’s rarely an easy way to export/import these.
Reinstall and Configure Plugins

Similar to themes, plugin files aren’t moved, and their settings often aren’t either.

  1. Network Activate any plugins that are essential for all sites on your multisite network.
  2. Individual Site Activate plugins that are specific to your new subsite from Plugins > Add New or Plugins > Installed Plugins on your new subsite.
  3. Reconfigure plugin settings. Just like themes, you’ll need to go through each plugin’s settings on your new subsite and reconfigure them to match your standalone site. This can include SEO settings, contact form configurations, security settings, caching, etc.

Redirects and DNS

This is the final hurdle to ensure your old site’s visitors land on the new one.

Domain Mapping (if applicable)

If your standalone site had its own custom domain (e.g., myoldsite.com), and you want to use that same domain for the subsite within your multisite, you’ll need to set up domain mapping.

  1. Ensure your multisite network supports domain mapping. Some hosting providers handle this automatically. You might need a plugin (like WP Ultimo, though that’s more for SaaS multisites) or manual server configuration.
  2. Update your DNS records. You’ll need to point the domain myoldsite.com to the IP address of your multisite server. This is done through your domain registrar or DNS management service. You’ll typically be changing A records.
  3. Map the domain within WordPress. In your multisite network admin, under Sites > All Sites, edit your new subsite. You’ll usually find an option to change the “Site Address (URL)” to your custom domain.
Set Up 301 Redirects

If you’re changing the URL structure significantly (e.g., moving from myoldsite.com to maindomain.com/myoldsite), or if your standalone site used a specific URL pattern that’s now slightly different, you’ll want 301 redirects.

  1. **On your old hosting platform (where the standalone site was), set up redirects.** This is usually done in your .htaccess file (for Apache servers) or through your host’s control panel.
  2. Redirecting Old URLs to New URLs:
  • Entire site redirect: If you’re moving olddomain.com to newdomain.com/subsite/, a simple host-level 301 redirect from olddomain.com to newdomain.com/subsite/ is usually sufficient for the main site.
  • Per-post/page redirects: If your permalink structure changed, or specific pages have new slugs, you’ll need more granular redirects. A plugin like “Redirection” can be very helpful on your new subsite once the primary domain is pointing correctly. However, if the old site is being completely decommissioned, you’ll need to apply rules at the old server level. For most cases, a wildcard redirect with RewriteRule ^(.*)$ https://newdomain.com/subsite/$1 [R=301,L] in the old site’s .htaccess should catch most things, assuming a similar path structure.

If you’re looking to migrate a standalone WordPress site into an existing multisite network, you might find it helpful to explore related resources that provide additional insights and tips. One such article can guide you through the process of managing your multisite effectively, ensuring a smooth transition for your content and settings. For more information, you can check out this informative piece on WordPress multisite management. This resource can help you understand the nuances of multisite configurations and optimize your new setup.

Final Checks and Troubleshooting

You’ve done the heavy lifting. Now, it’s time for some thorough testing.

Test Everything

Thoroughly Review Your Site

Go through your new subsite as if you were a visitor.

  • Click every menu item: Ensure all pages and posts load correctly.
  • Check images and media: Are all images displaying? Can you embed videos?
  • Test forms: If you have contact forms or other submission forms, send a test entry.
  • Review comments: Are all comments present and styled correctly?
  • Test any custom functionality: If your old site had special features, ensure they’re working.
  • Check mobile responsiveness: Does the site look good on various devices?
Clear Caches

If you’re using a caching plugin on the multisite, or server-level caching, clear it so you’re always seeing the most up-to-date version of your site.

Common Issues and Quick Fixes

  • “404 Not Found” errors: Usually a permalink issue. Go to your subsite’s Settings > Permalinks and simply save them again.
  • Missing images: Either the media import failed, or the file paths in the database are incorrect. Double-check your wp-content/uploads/sites/ID/ directory and ensure the files are there. You might need a plugin like “Better Search Replace” to update old image URLs if manual transfer methods didn’t update the database.
  • Broken styling/theme issues: This points to theme configuration (revisit Appearance > Customize or theme options) or missing theme files. Ensure your theme is correctly installed and activated for the subsite.
  • Plugin conflicts: Deactivate plugins one by one on the subsite to identify any causing issues. Reinstalling and reconfiguring problematic plugins might help.

By following these steps carefully, you should be able to successfully migrate your standalone WordPress site into your existing multisite network. It’s a process that demands attention to detail, but the long-term benefits of managing your sites under one roof can be well worth the effort. Good luck!