Some apps, mainly antivirus apps, drivers, other non-OS update stuff mostly demand a reboot after an installation or after an update ends.

I'd like to know, why? If an app changes its data or system data, a coder/app should manage changes itself and there surely are ways how to reload important stuff that app uses right from a running OS. I understand why drivers need to reboot system, but why for example antivirus apps?

  • 1
    One reason in Windows is most software installations make new registry entries, and some of these new entries require a restart to take effect, some registry entries are updated immediately, others require a restart, its a windows requirement, not something the software vendors do that causes this reboot requirement. I cannot speak for other non Windows OS's.
    – Moab
    Apr 12, 2016 at 18:36

2 Answers 2


A program's files can only be replaced if they are not currently in use. So to replace the executable of an anti virus program, that program needs to be stopped and restarted.

But stopping a security related software is a dangerous operation: while it isn't running and protecting the system, an attack could be successful and compromise your computer.

So the update just prepares the new files and instructs the OS to replace them at next reboot, before any dangerous activity could happen (hopefully).

Of course, also non-security related programs tend to do it like that, in which case, it's just lazyness. It's easyier to just reboot instead of coding a clean replacement installer.


You can do this in linux and OSX can without a reboot to some extent But windows requires a reboot. The best reason why is because the Resources or program are already in use.

When you restart the program it allows the programs to start fresh with any updates to be applied.

You cant stop most services or drivers in windows without rebooting because it will cause the system to become unstable. So its just better to reboot. Which is why most programs ask you to reboot now or later for the Install to actually become in effect.

OSX and Linux are built with a different layered os. Which rarely has them have to reboot when you make system changes.

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