# MP4 files cannot be opened for writing
**URL:** https://community.mp3tag.de/t/mp4-files-cannot-be-opened-for-writing/49164
**Category:** Support
**Created:** [June 1, 2020, 1:47am UTC](https://community.mp3tag.de/t/mp4-files-cannot-be-opened-for-writing/49164 "2020-06-01T01:47:45Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@OkieInCO](https://community.mp3tag.de/u/OkieInCO)
#### Post date: [June 1, 2020, 1:47am UTC](https://community.mp3tag.de/t/mp4-files-cannot-be-opened-for-writing/49164/1 "2020-06-01T01:47:45Z")
I thought I read that mp3tag works for editing tags on mp4 files. But, I'm getting an error message when adding a new thumbnail to an mp4 video, and it won't allow me to save it.
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [June 1, 2020, 6:44am UTC](https://community.mp3tag.de/t/mp4-files-cannot-be-opened-for-writing/49164/2 "2020-06-01T06:44:49Z")
See MP3tag's main page for supported file formats.
> **[Mp3tag - der universelle Tag Editor (ID3v2, MP4, OGG, FLAC, ...)](https://www.mp3tag.de/)**
>
> Mp3tag ist ein einfach zu benutzendes Programm zum komfortablen Bearbeiten von Tags in Audio-Dateien
> [@OkieInCO](#):
>
> But, I'm getting an error message
Which one?
---
### Author:  [@OkieInCO](https://community.mp3tag.de/u/OkieInCO)
#### Post date: [June 1, 2020, 2:59pm UTC](https://community.mp3tag.de/t/mp4-files-cannot-be-opened-for-writing/49164/3 "2020-06-01T14:59:19Z")
Here's a screen shot of the message.
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### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [June 1, 2020, 3:38pm UTC](https://community.mp3tag.de/t/mp4-files-cannot-be-opened-for-writing/49164/4 "2020-06-01T15:38:44Z")
This error message could have several root causes:
- you do not have sufficient access rights for these files (you should be the owner, being Admin is often not enough),
- the file is blocked by another program so that it cannot be written,
- the file is corrupt in some way.
Depending on what it is, the remedies vary.
---
### Author:  [@OkieInCO](https://community.mp3tag.de/u/OkieInCO)
#### Post date: [June 1, 2020, 5:36pm UTC](https://community.mp3tag.de/t/mp4-files-cannot-be-opened-for-writing/49164/5 "2020-06-01T17:36:00Z")
It could be number two on your list. At some point, even though the error message indicates that the file couldn't be written on, the thumbnail changed to the picture I used in the tag. So, I'm wondering if the error resulted due to the file residing in my OneDrive folder, and OneDrive is constantly backing it up to the cloud? Just a thought.
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### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [June 1, 2020, 5:38pm UTC](https://community.mp3tag.de/t/mp4-files-cannot-be-opened-for-writing/49164/6 "2020-06-01T17:38:27Z")
see e.g. here:
> [@"File Cannot Be Opened For Writing"](https://community.mp3tag.de/t/file-cannot-be-opened-for-writing/12416/20):
>
> Just an FYI. In Win 10 I had the same issue with some m4b files and found that they were being synced to OneDrive (Don't remember setting that up). You can tell by the status column in Explorer.
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### Author:  [@OkieInCO](https://community.mp3tag.de/u/OkieInCO)
#### Post date: [June 1, 2020, 6:09pm UTC](https://community.mp3tag.de/t/mp4-files-cannot-be-opened-for-writing/49164/7 "2020-06-01T18:09:50Z")
Yah. That sounds like that's the issue. I'll move the file to another folder and see what happens.
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### Author:  [@jewahe](https://community.mp3tag.de/u/jewahe)
#### Post date: [January 15, 2021, 5:00am UTC](https://community.mp3tag.de/t/mp4-files-cannot-be-opened-for-writing/49164/8 "2021-01-15T05:00:42Z")
I always use the following script to reset the ownership of my music files.
```auto
D:
CD {PATH to Storage Directory}
attrib -r -s -a *.mp3 /s
attrib -r -s -a -h /s /d
takeown /r /d y /f {PATH to Storage Directory}
icacls * /t /grant Everyone:F
pause
```
(assuming you're using windows).
---
### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [January 15, 2021, 2:12pm UTC](https://community.mp3tag.de/t/mp4-files-cannot-be-opened-for-writing/49164/9 "2021-01-15T14:12:09Z")