How to Actually Fix the All-in-One WP Migration 512MB Import Limit

If you’ve ever tried to migrate a WordPress site larger than 512MB using All-in-One WP Migration, you’ve probably hit a wall and not the one you expected.

I recently moved a website from one domain to another. The backup file was about 1 GB, and the plugin greeted me with: “Your file exceeds the 512 MB upload limit set by your host.” Sounds like a server issue, right? That’s what I thought too. Spoiler: it wasn’t.

What I Tried (And What Didn’t Work)

Following the plugin’s own documentation and various online guides, I went through every recommended fix.

Editing .htaccess — I added the suggested PHP values for upload_max_filesize, post_max_size, memory_limit, and max_execution_time outside the WordPress block. No error, but also no change. The limit stayed at 512MB.

Editing wp-config.php — I added @ini_set() calls for all the same values and increased WP_MEMORY_LIMIT to 2048M. Same result: the plugin still refused the upload.

Creating a .user.ini file — This one actually worked for changing the server-side PHP limits. I confirmed that upload_max_filesize and post_max_size were now set to 2048M on the server. But the plugin still blocked the import at 512MB.

Uploading via FTP — I uploaded the .wpress backup file directly to /wp-content/ai1wm-backups/ via FTP. The plugin recognized the backup under “Backups”, but the restore button prompted me to purchase the premium extension.

At this point, it became clear: the 512MB limit is not a server restriction. It is hard-coded into the plugin itself. No amount of PHP configuration changes will override it, because the plugin enforces its own cap regardless of what your server allows.

The Workaround That Actually Works

The solution is to use an older version of the plugin (v6.77) that allows you to edit the internal size limit.

1. Deactivate and delete the current version of All-in-One WP Migration from your WordPress installation.
2. Download version 6.77 it’s available on GitHub.
3. Install and activate the older version via Plugins → Add New → Upload Plugin.
4. Go to Plugins → Plugin Editor and select All-in-One WP Migration from the dropdown.
5. Open the file constants.php (inside the /lib/ folder).
6. Search for the line containing AI1WM_MAX_FILE_SIZE — it will have a value like 2 << 28.
7. Replace that value with a larger number in bytes. For example, 536870912 * 10 for a 5 GB limit.
8. Click Update File, then refresh the Import page. (Doesn’t work? Do it via FTP).

The import size limit should now reflect your new value. Upload your backup, and the restore will proceed without any premium extension.

The Bigger Issue

This is not a hosting problem. This is not a configuration problem. The 512MB restriction is a deliberate product decision, a hard-coded limit designed to funnel users toward the $69 Unlimited Extension.

That would be perfectly fine if it were communicated transparently. Instead, the plugin’s documentation sends users down a rabbit hole of server-side fixes that cannot possibly work, because the bottleneck was never the server.

After spending a lot of time adjusting .htaccess, wp-config.php, .user.ini, and even working with hosting support, the only thing that resolved the issue was bypassing the plugin’s own internal restriction.

Quick Reference: .user.ini Settings

If your server’s PHP limits are actually too low (which is a separate issue from the plugin limit), here’s the .user.ini configuration that worked for me. Place it in your WordPress root directory:

max_input_vars = 10000
max_execution_time = 300
upload_max_filesize = 2048M
post_max_size = 2048M
memory_limit = 2048M
max_input_time = 300

Remember to reset these values after your migration is complete.

Alternatives Worth Considering

If you’d rather avoid the workaround entirely, there are free migration plugins that don’t impose artificial size limits:

• Duplicator — packages your site into an installer and archive file, bypassing upload limits entirely
• WPvivid — offers key-based direct migration between sites in its free version
• UpdraftPlus — splits backups into smaller files automatically, no artificial caps

For a one-time migration, the version 6.77 workaround is quick and effective. But if you migrate sites regularly, switching to a tool that doesn’t gatekeep basic functionality might save you future headaches.