---
title: "Scanner Warnings and Errors - How to Handle Them"
url: https://phatdev.net/en/docs/sl-migrations/how-to-resolve-scanner-warnings-errors-and-timeout-issues
lang: en
updated: 2026-10-20
alternate:
  vi: https://phatdev.net/docs/sl-migrations/how-to-resolve-scanner-warnings-errors-and-timeout-issues
markdown: https://phatdev.net/en/docs/sl-migrations/how-to-resolve-scanner-warnings-errors-and-timeout-issues.md
---

# Scanner Warnings and Errors - How to Handle Them

Part of the doc set: [SL Migrations](https://phatdev.net/en/docs/sl-migrations.md)

> Explains the scanner's warnings and when they can be ignored.

## Scanner Warnings & Errors

The scanner runs before the build and checks your environment and site size. Results come in 3 levels:
- **PASS** - no action needed
- **WARN** - can be ignored but is worth fixing
- **FAIL** - must be fixed before building

## Server Setup

### PHP OpenSSL
**WARN** if missing - you cannot use remote storage (SFTP/FTP). Local builds still work. **Fix**: ask your hosting provider to install the `openssl` extension.

### Web Server
**INFO**: detects Nginx/Apache.

### MySQL Mode
**WARN**: some SQL modes (`STRICT_TRANS_TABLES`, `NO_ZERO_DATE`) can block a restore. The plugin handles most cases, but it warns you so you know.

## File Setup

### Files Total Size
**WARN** if > 1GB. **Fix**: exclude folders you do not need (cache, logs).

### File Count
**WARN** if > 100,000 files. The build will be slow. **Fix**: exclude folders with many small files (cache, thumbnail caches).

### Large Files
**FAIL** if a file exceeds the limit (500 MB by default). The plugin will NOT include that file in the backup.

**Fix**:
- Raise the limit in **Settings → Package → Large File Size**
- Or exclude that file and back it up separately

### Symlinks
**WARN**: a symbolic link was detected. The plugin follows symlinks → files may be duplicated. Exclude the folder containing the symlink if you do not need it.

### Directory Permissions
**FAIL**: the backup folder is not writable. **Fix**: set permissions on the `wp-content/backups-slm/` folder - see [Fixing permissions](https://phatdev.net/en/docs/sl-migrations/how-to-fix-file-permissions-issues).

## Database Setup

### Database Size
**WARN** if the database > 100 MB. The dump build will take time. **Fix**: optimize the database, delete old post revisions, spam comments and transients.

### Tables Without Triggers
**INFO** only.

### Table Engine
**WARN** if any table uses MyISAM (the old engine). A restore still works but you should convert to InnoDB.

### Table Row Count
**WARN** if a table has > 1 million rows. The dump and restore take a long time. Optimize by deleting old data.

## When the build still fails even though the scanner passes

The scanner only checks prerequisites. The build can hit other errors at runtime - see [Builds that get stuck](https://phatdev.net/en/docs/sl-migrations/how-to-resolve-builds-getting-stuck-at-a-certain-point).

## See also

- [Server resources](https://phatdev.net/en/docs/sl-migrations/how-to-manage-server-resources-cpu-memory-disk)
- [Dependency checks](https://phatdev.net/en/docs/sl-migrations/how-to-resolve-dependency-checks)