# Replace Function Not Working? **URL:** \ **Category:** Mac\ **Created:** [February 23, 2021, 3:33am UTC](https://community.mp3tag.de/t/replace-function-not-working/52094 "2021-02-23T03:33:54Z")\ **Posts on this page:** 1\ **Showing post:** 2
**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 23, 2021, 6:51am UTC](https://community.mp3tag.de/t/replace-function-not-working/52094/2 "2021-02-23T06:51:38Z")
Many thanks for your feedback — happy you like it! Your probably observing this in the context of renaming files. I've made some subtle changes on how special characters are treated with the Mac version: Invalid characters are automagically replaced by an underscore on field access, and by that, circumvents what I call the "AC/DC"-Problem. In the past, renaming with fields that contained a path separator char — it's the forward slash on macOS — would result in unwanted folders being greated, e.g., "AC" and "DC". Invalid characters are currently `/` and `:` (and some newline and control characters) and if you have the NTFS option enabled at Preferences \> General, the list of special characters extends to the invalid chars on Windows. So, it's unfortunately not possible to distinguish between the underscore that results from the automatic replacement of the `:` character and the one that is the result of the `/` replacement. --- _[View the full topic](https://community.mp3tag.de/t/replace-function-not-working/52094)._