Firefox Download Fix: Adjusting network.http.response.timeout Restores Resumable Downloads

The Problem

Firefox 28 and newer, meaning every modern version since around 2014, ships with the network.http.response.timeout preference set to 300 seconds. According to a write-up published on 2026-10-11, this default appears to interfere with resuming large downloads and with the general stability of big downloads overall.

The issue is not that servers refuse to resume. If a server does not support resumable downloads, no browser setting can help. The problem is that Firefox fails to resume a download that the server is perfectly willing to continue. The author notes that resumable downloads in Firefox appear to rely on connection timeouts rather than on the .part files they create, and that Firefox will happily ignore an existing .part file without the right configuration.

The Fix

Setting network.http.response.timeout to 0, or to a very large value, in about:config appears to make big downloads both resumable and at least somewhat more stable. The author admits not fully understanding why this works, but says experimental testing supports the change.

The behavior has been a known problem in some form since as far back as 2005. The author also suspects Firefox performs hidden retries before declaring a download failed, and that exceeding the timeout interferes with that process. This has not been confirmed against Firefox source code, as the author says they have no clue where to look.

Workarounds

For users who prefer not to change hidden preferences, the author found a manual .part file shuffle that can make Firefox resume downloads, though they describe it as too much hassle to bother with. As a non-Firefox workaround, the command wget -c -O "$filename" "$url" also works, and wget overall appears to be fairly stable for large downloads.

Sources: lunarwatcher.codeberg.page