# problems with filter, using upper case escape char
**URL:** https://community.mp3tag.de/t/problems-with-filter-using-upper-case-escape-char/1760
**Category:** Support
**Created:** [March 8, 2005, 8:05pm UTC](https://community.mp3tag.de/t/problems-with-filter-using-upper-case-escape-char/1760 "2005-03-08T20:05:57Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Cyrom](https://community.mp3tag.de/u/Cyrom)
#### Post date: [March 8, 2005, 8:05pm UTC](https://community.mp3tag.de/t/problems-with-filter-using-upper-case-escape-char/1760/1 "2005-03-08T20:05:57Z")
I was recently attempting to use the '/u' for uppercase letters in the filter. I could not get it work as i got 0 files back. I know i have uppercase letters in just about every tag so i should get all files. I then attempted to use the '/l' character, which worked just fine. I am wondering if anyone else could verify that this isn't something that only happens with my installation.
Cyrom
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### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [March 8, 2005, 8:24pm UTC](https://community.mp3tag.de/t/problems-with-filter-using-upper-case-escape-char/1760/2 "2005-03-08T20:24:15Z")
Cyrom,
the problem you had with the filter is a limitation of the filter feature. To make the filter more usable for common queries I've decided to always ignore upper- and lowercase.
Internally I'm using both the field content and the filter string in lowercase.
Best regards,
~ Florian
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### Author:  [@Cyrom](https://community.mp3tag.de/u/Cyrom)
#### Post date: [March 8, 2005, 8:27pm UTC](https://community.mp3tag.de/t/problems-with-filter-using-upper-case-escape-char/1760/3 "2005-03-08T20:27:24Z")
Oh Ok. That makes sense. Anyway...thanks for the quick reply and a superb program.
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### Author:  [@system](https://community.mp3tag.de/u/system)
#### Post date: [February 9, 2026, 12:19pm UTC](https://community.mp3tag.de/t/problems-with-filter-using-upper-case-escape-char/1760/4 "2026-02-09T12:19:20Z")