Windows 10 FLAC encoded music files can be damaged due to metadata editing and become unplayable.

Microsoft is aware of this new problem and provided the following solution. To prevent this issue for future FLAC music files, install May 25, 2021, KB5003214 CU Builds 19041.1013, 19042.1013, and 19043.1013 to protect your precious FLAC audio files.

This problem affects the following builds: Windows 10 Enterprise, version 2004 Windows 10 Home, version 2004 Windows 10 Pro, version 2004 Windows 10 Education, version 2004 Windows 10 Pro Education, version 2004 Windows 10 Pro for Workstations, version 2004 Windows 10 Pro, version 20H2 Windows 10 Enterprise, version 20H2 Windows 10 Education, version 20H2 Windows 10 Home, version 20H2 Windows 10 Pro Education, version 20H2 Windows 10 Pro for Workstations, version 20H2



This update addresses a metadata encoding issue that causes Free Lossless Audio Codec (FLAC) music files to become unplayable if their title, artist, or other metadata is changed.


This issue might occur when the FLAC files contain an ID3 frame before the FLAC header. The ID3 frame contains metadata such as title and artist. The FLAC property handler assumed that all FLAC files started with the 4-byte start code fLaC and did not take into account the ID3 frame at the beginning of the file. Therefore, the ID3 frame would be overwritten without the start code fLaC rendering the file unplayable.

For already damaged FLAC files, Microsoft has developed a script to repair damaged FLAC files. Read more here.

Download: Microsoft Script