# License is forgotten, mp3tag reverts to trial after starting
**URL:** https://community.mp3tag.de/t/license-is-forgotten-mp3tag-reverts-to-trial-after-starting/70737
**Category:** Mac
**Created:** [February 21, 2026, 7:01pm UTC](https://community.mp3tag.de/t/license-is-forgotten-mp3tag-reverts-to-trial-after-starting/70737 "2026-02-21T19:01:35Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@Herbert](https://community.mp3tag.de/u/Herbert)
#### Post date: [February 21, 2026, 7:01pm UTC](https://community.mp3tag.de/t/license-is-forgotten-mp3tag-reverts-to-trial-after-starting/70737/1 "2026-02-21T19:01:35Z")
After using mp3tag without any problems for years, recently it started asking for my license every time I start the app. When I input the serial, I get a message my copy is now licensed, but the next time I start the app, mp3tag is in trial mode again.
I’m running MacOS Big Sur (11.7). Maybe it has something to do with the recent update to 11.7.11?
It works fine on my other Mac running MacOS 26, latest version.
---
### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [February 21, 2026, 7:10pm UTC](https://community.mp3tag.de/t/license-is-forgotten-mp3tag-reverts-to-trial-after-starting/70737/2 "2026-02-21T19:10:21Z")
Have you changed anything with the permissions for files inside of `~/Library`, e.g., restored something from a backup or copied from another Mac?
It sounds like the changes to Mp3tag's configuration settings are not persisted across re-runs of the app.
---
### Author:  [@Herbert](https://community.mp3tag.de/u/Herbert)
#### Post date: [February 21, 2026, 7:22pm UTC](https://community.mp3tag.de/t/license-is-forgotten-mp3tag-reverts-to-trial-after-starting/70737/3 "2026-02-21T19:22:30Z")
Not that I’m aware of. I have not restored anything, or copied any system files. I have 4 days of my trial left, so something must have happened 10 days ago (right….?), and the last big thing I did, was install the 11.7.11 security fix. Which must have been 10 days ago.
Maybe the update changed some permissions?
---
### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [February 21, 2026, 7:27pm UTC](https://community.mp3tag.de/t/license-is-forgotten-mp3tag-reverts-to-trial-after-starting/70737/4 "2026-02-21T19:27:23Z")
It's a 7-day trial and only days you're using the app are counted.
Can you run the following commands in Terminal.app and copy the output?
```plaintext
id
ls -ld ~/Library/Containers/app.mp3tag.Mp3tag
ls -l ~/Library/Containers/app.mp3tag.Mp3tag/Data/Library/Preferences
plutil -lint ~/Library/Containers/app.mp3tag.Mp3tag/Data/Library/Preferences/app.mp3tag.Mp3tag.plist
```
---
### Author:  [@Herbert](https://community.mp3tag.de/u/Herbert)
#### Post date: [February 21, 2026, 7:34pm UTC](https://community.mp3tag.de/t/license-is-forgotten-mp3tag-reverts-to-trial-after-starting/70737/5 "2026-02-21T19:34:01Z")
Hope I did it correctly. Here’s the 4 commands with their output:
```auto
id
uid=501(Macmos) gid=20(staff) groups=20(staff),12(everyone),61(localaccounts),79(_appserverusr),80(admin),81(_appserveradm),98(_lpadmin),701(com.apple.sharepoint.group.1),33(_appstore),100(_lpoperator),204(_developer),250(_analyticsusers),395(com.apple.access_ftp),398(com.apple.access_screensharing),399(com.apple.access_ssh),400(com.apple.access_remote_ae),702(com.apple.sharepoint.group.2)
--
ls -ld ~/Library/Containers/app.mp3tag.Mp3tag
drwx------@ 6 Macmos staff 192 Feb 8 19:49 /Users/Macmos/Library/Containers/app.mp3tag.Mp3tag
--
ls -l ~/Library/Containers/app.mp3tag.Mp3tag/Data/Library/Preferences
total 0
lrwxr-xr-x 1 Macmos staff 51 Dec 27 2020 com.apple.security.plist -> ../../../../../Preferences/com.apple.security.plist
lrwxr-xr-x 1 Macmos staff 58 Dec 27 2020 com.apple.security_common.plist -> ../../../../../Preferences/com.apple.security_common.plist
--
plutil -lint ~/Library/Containers/app.mp3tag.Mp3tag/Data/Library/Preferences/app.mp3tag.Mp3tag.plist
/Users/Macmos/Library/Containers/app.mp3tag.Mp3tag/Data/Library/Preferences/app.mp3tag.Mp3tag.plist: file does not exist or is not readable or is not a regular file (Error Domain=NSCocoaErrorDomain Code=256 "The file “app.mp3tag.Mp3tag.plist” couldn’t be opened." UserInfo={NSFilePath=/Users/Macmos/Library/Containers/app.mp3tag.Mp3tag/Data/Library/Preferences/app.mp3tag.Mp3tag.plist, NSUnderlyingError=0x7fbd3dc0b3a0 {Error Domain=NSPOSIXErrorDomain Code=92 "Illegal byte sequence"}})
```
---
### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [February 21, 2026, 8:00pm UTC](https://community.mp3tag.de/t/license-is-forgotten-mp3tag-reverts-to-trial-after-starting/70737/6 "2026-02-21T20:00:00Z")
Yes, thank you, and the error in the last line looks suspicious.
Now please run
`defaults read app.mp3tag.Mp3tag 2>&1 | head -n 40`
If it produces an error, you can try with Mp3tag closed
```auto
mv ~/Library/Containers/app.mp3tag.Mp3tag ~/Desktop/app.mp3tag.Mp3tag.container.backup
```
and restart Mp3tag.
---
### Author:  [@Herbert](https://community.mp3tag.de/u/Herbert)
#### Post date: [February 21, 2026, 10:49pm UTC](https://community.mp3tag.de/t/license-is-forgotten-mp3tag-reverts-to-trial-after-starting/70737/7 "2026-02-21T22:49:45Z")
I got an error indeed with the first command, closed mp3tag, ran the other command, started mp3tag, entered my serial, restarted, and now it seems to work fine.
Let’s see if it stays like this the next few days, but for now thanks a lot! Amazing how fast you were able to help.
---
### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [February 22, 2026, 8:41am UTC](https://community.mp3tag.de/t/license-is-forgotten-mp3tag-reverts-to-trial-after-starting/70737/8 "2026-02-22T08:41:15Z")
Excellent, glad it's working now!
You can now also safely remove the folder `app.mp3tag.Mp3tag.container.backup` from your Desktop.
---
### Author:  [@system](https://community.mp3tag.de/u/system)
#### Post date: [March 1, 2026, 8:41am UTC](https://community.mp3tag.de/t/license-is-forgotten-mp3tag-reverts-to-trial-after-starting/70737/9 "2026-03-01T08:41:43Z")
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