Windows10 Photos app fails to open HEIC images after the HEVC extension is installed

You’ve installed the HEVC extension, but Photos still will not open HEIC images. HEIC is a HEIF image container and may require both HEIF Image Extensions and HEVC Video Extensions; the video codec alone is not always sufficient. Check Microsoft Store > Library for updates to Photos and both extensions, then close Photos and restart Windows. Open an affected file from a local folder, and confirm it is actually .heic rather than a damaged file with a renamed extension. Test a newly transferred phone photo. If that opens, re-copy the failing originals; if it does not, reset Photos from Settings > Apps > Microsoft Photos > Advanced options, using Repair first and Reset only if necessary. Reset can clear app settings, not your pictures. As a workaround, transfer photos using the phone’s compatibility conversion option or OneDrive’s conversion workflow. Do not download random codec packs or replace Windows media files