# Editing or just saving header data breaks WMP playback and file thumbnails in explorer

**URL:** <https://help.mkvtoolnix.download/t/editing-or-just-saving-header-data-breaks-wmp-playback-and-file-thumbnails-in-explorer/1234>\
**Category:** Help\
**Tags:** help, bug\
**Created:** [February 16, 2025, 12:53pm UTC](https://help.mkvtoolnix.download/t/editing-or-just-saving-header-data-breaks-wmp-playback-and-file-thumbnails-in-explorer/1234 "2025-02-16T12:53:32Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![darkrai](https://help.mkvtoolnix.download/letter_avatar_proxy/v4/letter/d/e9c0ed/32.png) [@darkrai](https://help.mkvtoolnix.download/u/darkrai)\
**Post date:** [February 16, 2025, 12:53pm UTC](https://help.mkvtoolnix.download/t/editing-or-just-saving-header-data-breaks-wmp-playback-and-file-thumbnails-in-explorer/1234/1 "2025-02-16T12:53:32Z")

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When I try to edit the file header or just load the file into the editor and save without changing anything both the preview in file explorer and windows media player playback breaks. VLC can still play the file but having to always provide a portable copy of VLC with everything is not exactly a good solution.  
Any idea/solution as to why that might happen?

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**Author:** ![mbunkus](https://help.mkvtoolnix.download/user_avatar/help.mkvtoolnix.download/mbunkus/32/11_2.png) [@mbunkus](https://help.mkvtoolnix.download/u/mbunkus)\
**Post date:** [February 16, 2025, 1:04pm UTC](https://help.mkvtoolnix.download/t/editing-or-just-saving-header-data-breaks-wmp-playback-and-file-thumbnails-in-explorer/1234/2 "2025-02-16T13:04:02Z")

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Read [this FAQ entry](https://gitlab.com/mbunkus/mkvtoolnix/-/wikis/All-tracks-vanished-after-mkvpropedit,-the-header-or-chapter-editors), please. Even though the premise seems to be different from what you describe, the underlying situation remains the same.

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**Author:** ![darkrai](https://help.mkvtoolnix.download/letter_avatar_proxy/v4/letter/d/e9c0ed/32.png) [@darkrai](https://help.mkvtoolnix.download/u/darkrai)\
**Post date:** [February 16, 2025, 1:13pm UTC](https://help.mkvtoolnix.download/t/editing-or-just-saving-header-data-breaks-wmp-playback-and-file-thumbnails-in-explorer/1234/3 "2025-02-16T13:13:06Z")

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Apologies.  
Didn’t connect the dots. This very much solves the problem.  
Thanks a lot!