# Cannot Change File Extension

**URL:** https://community.mp3tag.de/t/cannot-change-file-extension/63818
**Category:** Support
**Created:** [February 17, 2024, 7:46pm UTC](https://community.mp3tag.de/t/cannot-change-file-extension/63818 "2024-02-17T19:46:14Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![Florian](https://community.mp3tag.de/user_avatar/community.mp3tag.de/florian/32/5759_2.png) [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [February 17, 2024, 8:02pm UTC](https://community.mp3tag.de/t/cannot-change-file-extension/63818/2 "2024-02-17T20:02:15Z")

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Yes, the action from the first post of this topic does this successfully

> [@Change file extension to lowercase - Regular expression](https://community.mp3tag.de/t/change-file-extension-to-lowercase-regular-expression/59816):
>
> Seems like the regular expression thread is locked Previously found some nice examples there, why was it closed? Not an overly complex one but couldn't find it so posting here in case it's useful to someone else: Had a number of uppercase file extensions and was looking to convert them all to lowercase; there doesn't seem to be such a thing as the '"file extension" field so here's my take on it: Field : \_FILENAME Regular expression : \.(.\*)$ Replace with : .$lower($1) Cheers,

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