Why close all other applications before running installer?

Question

Most windows installers includes a recommendation that you "close all other applications before continuing". I can imagine this may have been necessary in old versions of windows. And it may be for a small number of installations now. But surely it isn't needed for most installs. Is it?

I'm creating an installer for my own (pretty simple) application now, and I find myself thinking - as I suspect many others have before me - 'it can't do any harm, and better safe than sorry'. But on the other hand I don't want to inconvenience people for no reason. So is there a reason to say it?

Answer 1

There usually isn't much of a reason, but most installers install DLLs and/or make registry or other changes that may effect or be effected by other applications.

Notably, anti virus software may lock files that your installer won't expect to be locked (including your new files) - at the very least it make sense to ask the user to disable that kind of software.

Answer 2

Only if you're going to update some file (most likely a dll and/or .exe) which is a common/shared one (ie: in \windows\system32).

If this is the case, it's either close the apps, or you'll have to reboot to complete the install.

Answer 3

Most probably just to release locks on resources which the installer needs which might be presently used by some other application that is running and there might as well be some other reasons for this.

Thanks

Answer 4

Agree and disagree with the answetr fromn ofir. It is most likely to do with the need to ensure that when registry files and such are edited or changed during instalation but I would highly doubt it has anything to do with anti-virus software. As stated very few people would be willing to install software that required someone to deactivate their anti-virus. Although many applications nowadays only require you to shut down either instances of the same program or ones that are using common files, unless they are going to involve a system reboot and that would largely just be to ensure no work is unsaved and thus lost by the reboot.