---
title: "Deprecation: #63603 - ExtendedFileUtility::$dontCheckForUnique is deprecated"
manual: "TYPO3 Core Changelog"
version: "main"
permalink: "https://docs.typo3.org/permalink/changelog:deprecation-63603-1668719172"
source: "Changelog/7.4/Deprecation-63603-ExtendedFileUtilitydontCheckForUniqueIsDeprecated.rst"
typo3-version: "7.4"
typo3-major: 7
type: "deprecation"
issue: 63603
forge: "https://forge.typo3.org/issues/63603"
tags: ["PHP-API", "FAL"]
rendered: "2026-09-30T21:29:40+00:00"
---

# Deprecation: #63603 - ExtendedFileUtility::$dontCheckForUnique is deprecated {#deprecation-63603-1668719172}

See [forge#63603](https://forge.typo3.org/issues/63603)

## Description {#description}

The ExtendedFileUtility `$dontCheckForUnique` flag has been marked as deprecated and replaced by
`$fileUtility->setExistingFileConflictMode()` with the possible options of the `TYPO3CMSCoreResourceDuplicationBehavior` enumeration.

## Impact {#impact}

Extensions still using `ExtendedFileUtility::$dontCheckForUnique` will throw a deprecation warning.

## Affected Installations {#affected-installations}

All installations with extensions that use `ExtendedFileUtility::$dontCheckForUnique`.

## Migration {#migration}

Change the `$fileUtility->dontCheckForUnique = TRUE` to `$fileUtility->setExistingFileConflictMode(DuplicationBehavior::REPLACE)`.