Microsoft Edge 148 Bug Freezes Browser During Large File Downloads — Here’s the Fix
A bug in Microsoft Edge version 148.0.3967.83 causes the browser to freeze and drives to spike to 100% active time during large file downloads, affecting users across home and enterprise environments.
The issue traces to a silent rollout of parallel downloading — a feature that splits large files into three concurrent data streams to increase transfer speeds.
What’s Causing It
Edge product manager Eric Lawrence confirmed the behavior on his text/plain blog, saying the browser now pre-allocates the entire destination file as a sparse file — a Windows file system technique that reserves space without immediately writing data — before any of the three download streams complete.
For a 24GB file, that means Edge attempts to block out the full physical space on disk at once.
The browser’s interface has no holding state for that operation, so it appears completely frozen while the pre-allocation runs.
Enterprise Networks Hit Hardest
IT administrators on the r/sysadmin subreddit report the bug triggers consistently when the browser’s “Ask where to save” prompt routes downloads to an SMB share — a standard network file-sharing protocol used in corporate environments.
Affected systems generate large, corrupt `.crdownload` temporary files and hang without recovery.
Several administrators said rolling fleet machines back to Edge 147.0.3912.98 stops the problem reliably.
Even on local drives, users report that downloads of files around 15GB or larger can lock systems hard enough to require a physical restart.
Killing the `msedge.exe` process tree from the command line does not resolve the disk thrashing, users said.
How to Fix It Without Rolling Back
Microsoft has not issued a patch or public statement on the bug as of publication.
Still, users can disable the feature directly inside the browser without downgrading their installation.
Entering `edge://flags/#enable-parallel-downloading` into the Edge address bar opens the experimental features panel, where setting the parallel downloading toggle to “Disabled” stops the behavior.
The fix survives Browser Restarts and applies immediately after the toggle changes.
Microsoft introduced parallel downloading as an opt-in experimental flag in earlier Edge versions before enabling it by default in the 148 release cycle.
