Windows 8 - Windows Defender Won't Open

[alfun]

I have tried to turn off avast and open Windows Defender but I get this message "This app has been turned off and isn't monitoring your computer.  If you're using another app to check for malicious or unwanted software, use Action Center to check that app's status."

Do I have to uninstall avast to be able to open Windows Defender?  I thought I opened it once before but I can't seem to get it to open.

I just want to do a manual scan with Windows Defender and have avast disabled.  I tried going to avast! shields control and clicking the "Disable permanently" option then opening Windows Defender in the Control Panel but it does not work.

[CraigB]

Yes that is correct, you would have to remove avast for Defender to become active again, this is because Defender on windows 8 is a full antivirus and not just spyware as it was on earlier versions of windows.

If you want to run an extra second opinion scanner then Malwarebytes would be the most recommended program to use and it's free, their paid Pro version also works in real time with avast without conflicts.

[alfun]

Yes that is correct, you would have to remove avast for Defender to become active again, this is because Defender on windows 8 is a full antivirus and not just spyware as it was on earlier versions of windows.

What about for Windows Vista and Windows 7?  Is Windows Defender also a full antivirus on these two operating systems?  Will avast also have to be uninstalled first?

[ky331]

No, on Vista & Win7, Windows Defender is "merely" an "anti-SPYWARE" program, which can co-exist with other anti-virus programs such as avast.

There is a much-heated debate as to how much protection, if any, one gains by using Defender (anti-spyware on 7/Vista) over just avast... but I'm not gonna get into that here.

[alfun]

If I were on Windows Vista or Windows 7 and using Windows Defender, can avast be used together with Windows Defender with no problems?  I have read that some people have problems and some have not.

If using avast on a Windows Vista or Windows 7 machine is it recommended to disable Windows Defender?

[CraigB]

As already mentioned avast will work with Defender on Vista and Win7 but we don't recommend using Defender due to it poor detection rate and a waste of system resources when running in realtime.

[mchain]

Yes that is correct, you would have to remove avast for Defender to become active again, this is because Defender on windows 8 is a full antivirus and not just spyware as it was on earlier versions of windows.

If you want to run an extra second opinion scanner then Malwarebytes would be the most recommended program to use and it's free, their paid Pro version also works in real time with avast without conflicts.

Other online webscanners such as ESET also available:  http://www.eset.com/us/online-scanner/  No need to turn off a/v real-time scanning using this free service.  (Note: Use of this scanner cannot/will not replace the need for an active resident a/v program installed on your system)

[alfun]

I think its stupid that you have to uninstall avast just to be able to open Windows Defender.

But anyways, thanks for all the help.

[ky331]

One needs to consider how Microsoft set up Windows Defender (full-fledged anti-virus) on Windows 8:   
1) It was included to guarantee all users would be protected from the outset... no one would receive a system without SOME antivirus present and running.  At the same time,
2) It was programmed to be "the anti-virus of last resort"... meaning it would only be active if Windows determined no other antivirus was present, active, and current.
2a) If you, or an OEM on your behalf, install/enable another anti-virus program, Defender automatically disables itself; but
2b) When you uninstall another anti-virus... or if that anti-virus is deemed no longer up-to-date... then Defender automatically re-enables itself to offer you continual protection.

It's rather an ingenious idea --- to guarantee a user will ALWAYS be protected... while at the same time, deferring to the presence of a third-party antivirus supplied by you [or the OEM supplier].   In so doing, Microsoft was able to avoid issues of forcing/dictating a monopoly position in the anti-virus market.

One of the problems that you need to consider:   even if you "disable" avast's run-time protection modules, its drivers and system files --- which were loaded during boot-up --- still remain intact.  And these can potentially lead to a conflict with Defender [or any other second anti-virus running on the system] despite avast no longer being "active".   Microsoft is actually looking out for you --- avoiding slowdowns and/or crashes --- by arranging things in this manner.

Hopefully, this may help you appreciate what otherwise would appear to be a "stupid" situation.

[alfun]

I agree that all those things you posted are good.  But I just wanted to open the Windows Defender program to look around in and play around with the program.  But to be able to even do this I would first have to uninstall avast, this is the stupid part that I refer to not all those things that you posted.

I was wondering if there are any startup options or definition update options for Windows Defender, this is why I wanted to get the program to open, but I guess I have to uninstall avast to get to these sort of options if they even exist?

[mchain]

I agree that all those things you posted are good.  But I just wanted to open the Windows Defender program to look around in and play around with the program.  But to be able to even do this I would first have to uninstall avast, this is the stupid part that I refer to not all those things that you posted.

I was wondering if there are any startup options or definition update options for Windows Defender, this is why I wanted to get the program to open, but I guess I have to uninstall avast to get to these sort of options if they even exist?

Microsoft is trying to do two things with Windows 8:

1.)  Protect all new users by providing a full-fledged antivirus program from the get-go on first use.  This is different from prior practice on new os installs on earlier versions of Windows.
2.)  Avoiding issues with running two active resident antivirus programs at the same time by automatically disabling Windows Defender when it detects a third-party install. 

Seems fair enough.

So, yes, you will have to uninstall avast! in order to run Windows Defender on W 8.  If you wish to do so, then use this tool,  http://www.avast.com/uninstall-utility after uninstalling avast! normally, and reboot.   You'll need to check to see if WD is enabled and running as it should be on restart.  If so, you're good to go.