---
title: "Troubleshooting"
manual: "TYPO3 Explained"
version: "12.4"
permalink: "https://docs.typo3.org/permalink/t3coreapi:troubleshooting-index@12.4"
source: "Administration/Troubleshooting/Index.rst"
rendered: "2026-10-21T15:29:37+00:00"
---

> [!WARNING]
> **Attention**
>
> TYPO3 v12 has reached end-of-life as of April 30th 2026 and
> is no longer being maintained. Use the version switcher on the top
> left of this page to select documentation for a supported version of TYPO3.
>
> Need more time before upgrading?
> You can purchase Extended Long Term Support (ELTS) for TYPO3 v12 here:
> [TYPO3 ELTS](https://typo3.com/services/extended-support-elts).

# Troubleshooting {#troubleshooting-index}

**[TYPO3](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-typo3@12.4)**

-   [Reset Backend Administrative User Passwords](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-backend-admin-password@12.4)
-   [Reset The Install Tool Password](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-install-tool-password@12.4)
-   [Enabling Debug Mode](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-debug-mode@12.4)
-   [Caching](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-caching@12.4)

**[System Modules](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-system-modules@12.4)**

-   [Log](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-system-modules-log@12.4)
-   [DB Check](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-system-modules-dbcheck@12.4)
-   [Configuration](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-system-modules-configuration@12.4)
-   [Reports](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-system-modules-reports@12.4)

**[PHP](https://docs.typo3.org/permalink/t3coreapi:examples-debug-php@12.4)**

-   [PHP Modules](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-php-modules@12.4)
-   [PHP Caches, Extension Classes](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-php-caches-extension-classes-etc@12.4)
-   [Opcode cache messages](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-php-troubleshooting-opcode@12.4)

**[Web server](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-webserver@12.4)**

-   [Apache - enable mod_rewrite](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-enable-mod-rewrite@12.4)
-   [Apache - adjust ThreadStackSize (Windows)](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-adjust-threadstacksize-on-windows@12.4)

**[Database](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-database@12.4)**

-   [MySQL - character sets](https://docs.typo3.org/permalink/t3coreapi:troubleshooting-character-sets@12.4)