Fix WordPress Migration Errors: Common Failures and Solutions

WordPress migration errors usually come from four places: corrupted database serialization, wrong URLs in wp_options, incompatible PHP versions, or incomplete file transfers. The fix is almost always diagnostic first — identify the symptom, check the log, apply the targeted fix — not reinstalling WordPress from scratch.

If the live site is broken right now and you have a pre-migration backup, consider rolling back first per your WordPress migration rollback plan, then fixing offline on staging.

Error: White screen of death (WSOD)

Symptoms: Blank white page on front-end and/or admin. HTTP 500 in browser dev tools.

Common causes:

• PHP fatal error from incompatible plugin or theme on new PHP version
• Memory limit too low on new host
• Corrupted wp-config.php during edit
• Missing or wrong database credentials

Fix steps:

1. Enable debugging in `wp-config.php`:

“`php

define('WP_DEBUG', true);

define('WP_DEBUG_LOG', true);

define('WP_DEBUG_DISPLAY', false);

“`

1. Check `wp-content/debug.log` and the server PHP error log (hosting panel → Error Logs).
2. Increase memory: `define('WP_MEMORY_LIMIT', '256M');` in wp-config.
3. Disable all plugins via SFTP: rename `wp-content/plugins` to `plugins_disabled`. If site loads, re-enable plugins one folder at a time.
4. Switch to a default theme: rename active theme folder, WordPress falls back to Twenty Twenty-Four.
5. Verify database credentials in wp-config match the new host's database.

PHP version mismatch: Source ran PHP 7.4, destination runs PHP 8.2. Old plugins throw fatal errors. Fix: temporarily set PHP 7.4 on destination if available, update plugins, then upgrade PHP.

Error: Redirect loop (ERR_TOO_MANY_REDIRECTS)

Symptoms: Browser shows "too many redirects." Often after enabling SSL on new host.

Common causes:

• `siteurl` and `home` in wp_options mismatch with actual URL
• Really Simple SSL or host force-HTTPS conflicts with Cloudflare SSL mode
• wp-config `WP_HOME` / `WP_SITEURL` constants conflict with database values
• .htaccess rewrite rules duplicated

Fix steps:

1. Check wp_options via phpMyAdmin:

“`sql

SELECT option_name, option_value FROM wp_options WHERE option_name IN ('siteurl', 'home');

“`

Both must match your live URL exactly (including `https://` and no trailing slash unless intentional).

1. Remove temporary wp-config URL constants if DNS cutover is complete:

“`php

// Remove these if present:

// define('WP_HOME', '…');

// define('WP_SITEURL', '…');

“`

1. Cloudflare SSL: set mode to Full (strict) if origin has valid SSL. "Flexible" with origin force-HTTPS causes loops.

1. Reset .htaccess to WordPress default:

“`apache

# BEGIN WordPress

<IfModule mod_rewrite.c>

RewriteEngine On

RewriteRule .* – [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]

RewriteBase /

RewriteRule ^index.php$ – [L]

RewriteCond %{REQUEST_FILENAME} !-f

RewriteCond %{REQUEST_FILENAME} !-d

RewriteRule . /index.php [L]

</IfModule>

# END WordPress

“`

Re-save permalinks in admin after restoring.

Error: Broken images and media

Symptoms: Image placeholders, 404 on uploads, correct paths in editor but broken on front-end.

Common causes:

• Absolute URLs in post content still pointing to old domain
• `upload_url_path` or `upload_path` in wp_options set incorrectly
• wp-content/uploads folder not transferred completely
• Wrong file permissions on uploads directory

Fix steps:

1. Verify `wp-content/uploads/` exists on new host with full year/month folder structure.
2. Run serialization-safe search-replace: old domain → new domain (WP-CLI: `wp search-replace 'https://old.com' 'https://new.com' –all-tables`).
3. Check wp_options:

“`sql

SELECT * FROM wp_options WHERE option_name IN ('upload_path', 'upload_url_path');

“`

Both should typically be empty (WordPress uses defaults). If set to old paths, clear them:

“`sql

UPDATE wp_options SET option_value = '' WHERE option_name IN ('upload_path', 'upload_url_path');

“`

1. Set uploads directory permissions to 755 (directories) and 644 (files).

Error: Cannot log in to wp-admin

Symptoms: Login page loads but credentials fail, or login redirects back to login, or cookies not sticking.

Common causes:

• `siteurl` points to old domain (cookie domain mismatch)
• HTTPS mismatch (cookie secure flag)
• Security plugin blocking new IP
• Full disk on new host

Fix steps:

1. Fix siteurl/home in database (see redirect loop section).
2. Clear browser cookies for the domain.
3. Define cookie domain in wp-config if using subdomains:

“`php

define('COOKIE_DOMAIN', '.yourdomain.com');

“`

1. Reset password via WP-CLI: `wp user update admin –user_pass=NewPassword123`
2. Or reset via phpMyAdmin: use MD5 hash temporarily or WordPress password reset function in functions.php (remove after use).
3. Disable security plugin via SFTP rename if it blocks login from new IP.

Error: Broken layout / missing CSS

Symptoms: Unstyled HTML, default browser fonts, layout collapsed.

Common causes:

• Mixed content — CSS loaded over HTTP on HTTPS page (browser blocks)
• CDN still pointing to old host
• Page builder CSS not regenerated (Elementor, Divi)
• Cache plugin serving stale paths

Fix steps:

1. Run serialization-safe search-replace for `http://` → `https://` on site URL.
2. Regenerate page builder assets: Elementor → Tools → Regenerate CSS; Divi → Theme Options → Builder → Clear cache.
3. Purge all caches: plugin, host, CDN, browser.
4. Check browser console for blocked mixed-content requests.

Error: Serialized data corruption

Symptoms: Widgets disappeared, theme customizer reset, plugin settings blank, random data loss.

Cause: Raw SQL find-and-replace on the database changed string lengths inside PHP serialized arrays without updating the length prefix. WordPress cannot unserialize the data.

Fix steps:

1. Restore database from pre-search-replace backup — fastest fix if available.
2. Re-run replace with a serialization-aware tool:

– WP-CLI: `wp search-replace 'olddomain.com' 'newdomain.com' –all-tables`

– Better Search Replace plugin with "Run as dry run" first, then live with serialization handling

1. For corrupted options, delete the broken row and reconfigure the plugin/theme (last resort):

“`sql

DELETE FROM wp_options WHERE option_name = 'widget_text';

“`

Then re-add widgets manually.

Deep reference: WordPress database migration guide.

Error: 404 on all pages except homepage

Symptoms: Homepage works; every other page 404.

Cause: Permalink rewrite rules not flushed; .htaccess missing or nginx config incomplete.

Fix:

1. Settings → Permalinks → Save Changes (no edits needed).
2. Verify .htaccess exists in site root with WordPress rewrite block.
3. On nginx hosts: confirm `try_files` directive includes WordPress pretty permalink rules (host support can verify).

Error: Contact forms and email not working

Symptoms: Forms submit but no email arrives; WooCommerce order emails missing.

Cause: SMTP credentials not migrated, host mail() function disabled, SPF/DKIM not updated for new IP.

Fix:

1. Re-enter SMTP plugin credentials (WP Mail SMTP, FluentSMTP, etc.).
2. Send test email from SMTP plugin dashboard.
3. Check spam folder.
4. If using host mail(): many managed hosts disable it — switch to SMTP or transactional service (SendGrid, Mailgun, Amazon SES).
5. Update SPF record if sending from new server IP.

Error: WooCommerce checkout broken

Symptoms: Cart empty after add, checkout infinite spinner, payment fails.

Fix:

1. Purge all caches with WooCommerce cache exclusions verified.
2. Re-authenticate payment gateway (Stripe, PayPal) on new domain — update webhook URLs in gateway dashboard.
3. Confirm SSL valid on checkout page.
4. Check Action Scheduler for failed jobs: WooCommerce → Status → Scheduled Actions.
5. Re-save permalinks and WooCommerce → Settings → Advanced → page setup.

When to stop DIY and hire a repair

Call for help when:

• No clean backup exists
• Database serialization is corrupted across multiple tables
• Live ecommerce site is losing orders
• You have spent 4+ hours without resolution
• Multisite or custom table prefix involved

Migration repair typically runs $300–$1,200 (estimate). See WordPress migration cost and when to hire WordPress migration help.

Prevention: avoid these errors next time

Follow the WordPress migration checklist:

• Verified backup before any changes
• Serialization-safe search-replace only
• Test on destination before DNS cutover
• Full SEO checklist if URLs change

FAQs

Can I fix migration errors without losing content?

Yes, if the database is intact. Most fixes are configuration — URLs, permissions, SSL, permalinks — not content deletion.

Should I restore backup or try to fix forward?

If live site is broken and backup exists: rollback first, fix on staging. If no backup: fix forward carefully with debug logging enabled.

Why did my migration plugin cause errors?

Plugins hit upload size limits, timeout on large tables, or run non-serialization-safe replaces internally. See All-in-One WP Migration vs manual.

How do I know if serialization is corrupted?

Widgets missing, customizer blank, specific plugin settings reset while posts intact. Check `wp_options` for values starting with `a:` or `s:` that look truncated.

Will fixing errors hurt SEO?

Fixing errors helps SEO. Leaving redirect loops or 404s hurts SEO. Implement 301 redirects if URLs changed during a botched migration.

—

Broken migration recovery is a common repair job. WordPress migration services include forensic diagnosis and clean re-migration.

Book a free 15-minute migration consult.