How Software Updates Work and What to Do When One Fails

What to take away

What an update changes

An update replaces or adds code, data or settings. The label may say patch, security update, upgrade, driver, firmware or system file. The scope differs more than the name suggests.

Microsoft separates a quality update, which is an incremental monthly update with bug fixes, feature improvements and security resolutions, from a feature update, which is released annually and includes the earlier quality updates. Apple, Google and phone makers use their own names, but the pattern is similar: frequent smaller fixes and a larger yearly release. The wider taxonomy of patch, upgrade, firmware and definition updates is set out in update types compared.

Why it matters: the U.S. National Institute of Standards and Technology frames patching as preventive maintenance for computing technology (SP 800-40 Rev. 4, April 2022). That guide is written for organisations, but its sequence suits a household: know what you have, decide what is urgent, use the official channel, check that it worked.

Read release notes when the consequence matters, but a short note does not mean a low-value fix. Apple states that it does not disclose, discuss or confirm security issues until an investigation has occurred, so its security releases page is where fixes are listed afterwards.

Automatic or manual

Automatic updating shortens the gap between a fix being released and being installed. CISA recommends enabling automatic updates where available, and suggests applying them on trusted networks such as home or work rather than airport or hotel networks. Manual checks still matter, because delivery can pause after an error, a full drive or the end of support.

Sources for the table are Apple's guides for iPhone and iPad and Mac, Google's Android update page and Microsoft's Windows Update troubleshooting page.

Android has two layers worth knowing. Under Settings, About phone, Android version, Google lists the Android version, the security update, the Google Play system update and the build number. Google says most system updates and security patches install automatically, and a download that does not finish is retried over the next few days.

Updates can arrive in stages. Google says update schedules vary by device, manufacturer and mobile carrier, so a friend's phone may get an update before yours.

Before and after an install

Before:

After:

CISA's guidance on patches (February 2023) says to download updates only from trusted vendor sites and to treat emails that claim to attach an update with suspicion. An unsolicited prompt to install an update should send you to the device's own settings, not to the link it gives.

Support has an end date

An unsupported device may still work, but it stops getting security fixes. These are the official dates and rules that matter most.

Before retiring a device, back up what you need, sign out of accounts, erase it by the maker's current instructions, and use a safe recycling route. For connected home products, track support dates alongside the other maintenance in the smart home systems guide.

When an update will not appear, download or install

"The update failed" can mean five different things. Find the stage, then use the vendor's fix for that stage, one change at a time.

iPhone and iPad. Apple's won't update page lists these in order: check the model is supported, free storage (Offload Unused Apps under Settings, General, iPhone Storage), use Wi-Fi without other downloads, retry on the same network then another network or a Mac, and keep the device connected to power. If it still fails, delete the downloaded update in Storage and download it again, then try a Mac. Apple lists recovery mode as a later step, for a device where the Apple logo stays on screen for several minutes without a progress bar.

Windows. Microsoft's troubleshooting page puts the steps in this order: run the Windows Update troubleshooter (Settings, System, Troubleshoot, Other troubleshooters in Windows 11), check power and internet, disconnect unneeded external hardware, clear the update cache, check the date and time, update third-party drivers, free disk space, run Windows Update again, and restart. It lists error codes such as 0x80070057 and 0xC1900101, each with its own steps. For an update stuck at 0% or 100% it advises restarting, then checking the connection and free space. At 51 to 99% it advises checking for updates again or running the troubleshooter. The command-line steps on that page need administrator rights, so follow them exactly or ask a technician.

Android. Google says to connect to Wi-Fi, charge to at least 75% and check for storage warnings. Failed downloads retry on their own for a few days.

Mac. Apple says to keep the Mac awake with the lid open, and expect several restarts.

Editorial suggestion: when a step does not help, undo any temporary setting you changed, such as turning off a VPN or security tool, before trying the next idea. Router and connection checks are in home network problems and fixes. Avoid commands from old forum posts, and avoid uninstalling a security update unless the vendor's own guidance says so.

When you contact support, give them: product and model, old and attempted version, the update name, the exact error text or code, the time and stage of failure, the power, storage and network state, and what you already tried.

Sources