Windows11 File Explorer freezes when opening a folder with many SVG or HEIC files

Your slowdown is specific to folders with many SVG or HEIC files, and thumbnails make it worse, so Explorer’s thumbnail decoding or cache path is the likely bottleneck rather than disk speed alone. First install Windows and Store updates, then restart. In File Explorer Options, temporarily enable “Always show icons, never thumbnails”; if the delay disappears, clear the thumbnail cache with Settings > System > Storage > Temporary files > Thumbnails, then re-enable previews. Confirm the Microsoft HEIF Image Extensions are installed and current. Next test a new folder containing batches of the same files to identify one malformed image. Run sfc /scannow, followed by DISM /Online /Cleanup-Image /RestoreHealth from an elevated Terminal. If the problem remains, perform a clean boot and test again to exclude third-party shell extensions or codec handlers. Record the file count and formats, then report it through Feedback Hub if Explorer stalls.