# \[X\] Mixed Case on Mac OS Sierra not working : "file already exists"

**URL:** <https://community.mp3tag.de/t/x-mixed-case-on-mac-os-sierra-not-working-file-already-exists/19115>\
**Category:** No Bugs\
**Created:** [July 3, 2017, 6:07pm UTC](https://community.mp3tag.de/t/x-mixed-case-on-mac-os-sierra-not-working-file-already-exists/19115 "2017-07-03T18:07:57Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![ohrenkino](https://community.mp3tag.de/user_avatar/community.mp3tag.de/ohrenkino/32/4843_2.png) [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)\
**Post date:** [July 6, 2017, 7:03am UTC](https://community.mp3tag.de/t/x-mixed-case-on-mac-os-sierra-not-working-file-already-exists/19115/4 "2017-07-06T07:03:10Z")

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> [@thfrere](#):
>
> ... or am I doing something wrong ?...v2.82 on Mac OS Sierra

MP3tag is still a Windows application.  
So somewhere, there is an emulator running. And NTFS (Windows) is not case-sensitive.  
To rename a file you cannot only change the case of a letter, you really have to rename it to a new filename (like add an underscore at the end), then apply the new case, then remove the underscore.  
No MP3tag bug but due to your environment.

in [Upper case](https://community.mp3tag.de/t/19132/9)  
you find an example how to rename files in principle. Perhaps the function $caps() is better for you.

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