Why does Adobe Acrobat Reader require a restart on update?

Why does Adobe Acrobat Reader require a restart when you update it? It's a piece of software that reads PDFs. Just what else is it installing/updating that requires a total OS reboot to "complete" the installation?

A bit of Googling indicates that it's to allow the OS to install the Adobe "Speed Launcher" - is this it or are there other components that are more tightly into the OS that it must absolutely have to have closed so that it can update them?

Edit: Any way to give half points to the two users that gave plausible explanations for this particular issue? I'm under the impression a combination of both of these answers is the reason why the restart is required, unless anyone has additional knowledge of what goes on behind the scenes are an Adobe update.

Solution 1:

There's a lot of folk wisdom that Adobe Acrobat Reader requires a reboot because of its Speed Launcher.

This is not, in fact, true. Speed Launcher installs itself in the Windows Explorer "All Users" Startup folder. Thus invoking it after installing it only requires that one log off and then log back on again. Indeed, one could just run the Speed Launcher program directly, from the shortcut in the startup folder, to start it if one wanted to, without even logging off and back on. After all, that's all that's really happening at log on.

Adobe Acrobat Reader requires a reboot because of the download program that it uses as part of installation. This is NOS Micro's getPlus. getPlus installs a "getPlus Helper Service" (running getPlus_HelperSvc.exe) to run on the first reboot after downloading the package that it is being used to install. This helper deletes the getPlus programs from the system, on the grounds that after installation the download manager is no longer needed.

Adobe Updater also sets up things that are run later. Again, however, it does not in fact require a reboot to run them. As one can see from Adobe's description of how to manually unstick Adobe Updater when it fails to complete the process on its own, Adobe Updater installs per-user run commands that are executed at log-on. Thus, again, all that is in fact required is to log off and log back on again, not restart the whole system.

Solution 2:

The main reason Reader is going to need a reboot after updating is because the ActiveX component and Explorer Shell Extension have been updated. Since these items are almost certainly being held open by Explorer (remember, Explorer.exe also hosts the desktop) or Internet Explorer, they can't be updated while either of those programs are running. The replacement of the actual file is scheduled for reboot, and you get prompted that it needs done.

The alternative is to make sure that all instances of Explorer and IE are shut down (for all logged-in users) before running the installer.

Solution 3:

If you block or stop the speedlauncher from running, you generally can ignore the restart request from the update app.

Most Adobe updates do not attempt to reset speedlauncher, so you do not generally have to re-remove it after updates.