The Unwanted Upgrades
Ubuntu relies heavily on “Snaps,” a containerized software packaging format. Unlike traditional APT packages that wait for you to run sudo apt update, the Snap daemon (snapd) is designed to automatically check for and install updates in the background, up to four times a day. While this ensures you always have the latest security patches for applications like Firefox or Slack, it can be disastrous for production environments or developers relying on a specific, stable version of a tool. An automatic, silent update might break compatibility, change the user interface, or consume network bandwidth at the worst possible time.
Delaying and Holding Snap Updates
While Canonical (the makers of Ubuntu) strongly discourages completely disabling Snap updates, you can use built-in configuration commands to stop Ubuntu from automatically refreshing Snap packages during your working hours or hold them indefinitely.
Open a terminal window (Ctrl+Alt+T). To restrict automatic updates to a specific, narrow time window (e.g., only between 2:00 AM and 4:00 AM on Sundays), type the following command: sudo snap set system refresh.timer=sun,02:00-04:00. If you need to stop a specific package from updating entirely because you need to stay on its current version, you must use the “hold” feature (available in newer versions of snapd). To freeze a package, type sudo snap refresh --hold [package_name] (e.g., sudo snap refresh --hold firefox). The system will no longer attempt to auto-update that specific application. To resume automatic updates for that package later, simply run sudo snap refresh --unhold [package_name].