Most of the time you do not need to restart your computer after uninstalling a program, but there are times when Windows will ask you to do so for a particular program. Can shutting your computer down work just as well as a complete restart? Today’s SuperUser Q&A post has the answer to a curious reader’s question.

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

The Question

SuperUser reader Leo King wants to know if shutting down a computer will work just as well as a restart after uninstalling an application:

When I uninstall an application, it says that I should either restart the computer now, or manually restart later. Will it make any difference if I shut the computer down instead? What’s the difference between the shutdown and restart operations?

Does it matter which process is used after uninstalling an application?

The Answer

SuperUser contributor LPChip has the answer for us:

The Process Explained

When you install or uninstall a program, it will register or unregister the usage of one or more .dll files.

.dll files are placed in the Windows system32/syswow64 directory when installed, and they are common files for many applications. These files often are in use at the time of uninstalling a program and, as such, Windows has a built-in system to check for unused (after uninstalling, no other program will be using these files anymore) .dlls at shutdown. This will remove them when the applications that were using them are terminated (basically the uninstaller tells Windows to verify the files for deletion).

When Windows has closed the program, it will then delete any file that is no longer assigned to a program to clean up the computer.

Is rebooting necessary?

You may be wondering, if that is all there is to it, is rebooting necessary? Yes and no. Basically, you have to make sure Windows will shut down properly or risk leaving unnecessary files behind. If you know your computer is stable, and you will be rebooting it in a matter of hours, you really do not need to reboot your computer right now.

If you regularly put your computer into sleep/hibernation mode and want to avoid rebooting as much as possible, it would be better if you rebooted after uninstalling an application because sleep/hibernation may cause a system to shut down unexpectedly in the long run (which can keep files on your computer that do not need to be there anymore).

Is it harmful if these files remain on my computer?

Technically speaking, no. It is a waste of disk space and, if it happens with too many files, it may slow your computer down because every .dll file that is loaded with Windows will be adding to the resources used to operate your computer.

Is there a difference between rebooting and shutting down?

Both options will close the programs and run the necessary clean-up routines, so both are fine to use. Windows just notifies you to reboot because that way it can guarantee that your system is being kept clean and tidy.

Is it okay if I hold the power button so that the computer is turned off immediately?

No. This is not a normal shutdown, and thus Windows will not be able to run the cleanup routine. You can see this option as being identical to Windows crashing.

Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.

Akemi Iwaya
Akemi Iwaya has been part of the How-To Geek/LifeSavvy Media team since 2009. She has previously written under the pen name "Asian Angel" and was a Lifehacker intern before joining How-To Geek/LifeSavvy Media. She has been quoted as an authoritative source by ZDNet Worldwide.
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