Q&A Is reinstalling Windows needed after changing AV?

mlnevese

Level 24
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May 3, 2015
1,375
I’ve never had trouble with leftover drivers after using an uninstall tool from the vendor, this is great advice.


I recently uninstalled Kaspersky from a machine and even after running the uninstall tool I still had a network driver installed, which I only discovered by chance when checking other problem in Device Manager. But even in the month or so it remained in the machine, it didn1t cause any troubles and all I had to do was to tell Device Manager to uninstall the device.
 

Dave Russo

Level 15
Verified
May 26, 2014
749
Have you looked at your Registry editor? ,I often try many Av"s (always gone back to Kaspersky, guess its the one I feel most comfortable with) anyway if you click on 2nd one down HKEY-Currant User then scroll down to software, there you will see {sometimes} programs with some remnant on your computer,right click and delete,also Try HKEY_Local_Machine and click software and once again there often is remnants there same right click and delete. If not sure how to get to registry editor just type in your lower left search bar regedit and it will pop up.
 

roger_m

Level 34
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Dec 4, 2014
2,320
@roger_m : sorry, too lazy myself to check this right now, but have you found HiBit to be comparable in successfully removing name-brand antivirus remnants? Like all of them: drivers, registry keys, folders.
If you use its installation monitoring, where it takes before and after snapshots you install an antivirus, it should be able to remove all remaining traces. However, if you are just using it scan for leftovers, when it hasn't monitored the install, you can expect it to miss some things. This is also an issue with Revo and other uninstallers when they are just scanning for leftovers.
 

Gandalf_The_Grey

Level 50
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Content Creator
Apr 24, 2016
3,919
AV Unistaller tool available in another thread in the forum still detects Norton that came installed in my notebook as installed. I never found the remaining files. Still had no trouble with it.
Did the Antivirus Removal Tool find any leftovers?
The thread:
Another option is:
 

mlnevese

Level 24
Verified
May 3, 2015
1,375
Did the Antivirus Removal Tool find any leftovers?
The thread:
Another option is:

I completely forgot Farbar existed :) Fixed Norton and found a Windscribe entry as well. Thanks :)
 

Spawn

Administrator
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Staff member
Jan 8, 2011
21,069
including WD, Bitdefender Free and the paid Bitdefender Antivirus Plus. I also tried out KSC Free a couple of times in the last 3 or 4 months. I tried out the different AV's looking for one I liked well enough to keep. I downloaded Avast Free a few days ago and so far it is working fine. Before I downloaded Avast I did a system restore back to the previous version of my laptop with WD. Then I installed Avast and I believe I will keep it.
Microsoft Defender will remain on your system regardless of using another Antivirus or not, and automatically reactivates upon uninstallation of any third-party Antivirus software. You can optionally use a limited mode of Microsoft Defender Antivirus with third-party Antivirus via it's Periodic Scanning feature. More info.

Security vendors provide Antivirus Removal Tools for broken uninstalls, but can be used before installing another AV software.

Removal Tools:
For Bitdefender: Uninstall Bitdefender
For Avast: Avast Uninstall Utility | Download aswClear for Avast Removal
For Kaspersky: Removal tool for Kaspersky applications (kavremover)

*Reinstalling the OS should not be an issue unless you are experiencing major problems with the OS.

Edit: *Clarification for when to reinstall the OS.
 
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shmu26

Level 85
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Jul 3, 2015
8,072
You usually won't have problems after uninstalling an AV and going back to Windows Defender. But the chance of issues will rise when you install and uninstall a second AV, and then another...
Yes, you can use the more aggressive AV removers, but they also can cause issues, sometimes serious ones.
The best and safest policy is to restore a system image, rather than simply uninstalling an AV.
 

FALC0N

New Member
Mar 29, 2021
9
Thanks for all the advice here. I used the Bitdefender Free and Paid removal tools to remove both versions of Bitdefender. It took some searching though to find the remover for BD Free, I found it here, thanks to the MT forums. I ran the Kaspersky removal tool and there was a Kaspersky folder it left over that had about 8 different files in it, I could no get rid of it and it was preventing WD from turning back on. Revo could not get rid of that folder either......

Are you sure you were using Revo correctly? I have never had it fail. It tears through everything. Including Kaspersky.

I have a very noob type question, I searched here and Google but did not really find my answer. I am on Windows 10 2004 with 8 GB ram on a basic laptop. I have used several AV programs over the last 6 months, including WD, Bitdefender Free and the paid Bitdefender Antivirus Plus. I also tried out KSC Free a couple of times in the last 3 or 4 months. I tried out the different AV's looking for one I liked well enough to keep. I downloaded Avast Free a few days ago and so far it is working fine. Before I downloaded Avast I did a system restore back to the previous version of my laptop with WD. Then I installed Avast and I believe I will keep it.

I am wondering if it is necessary to reinstall Windows again since I have changed AV's so many times recently, or is my system restore back to a known good point all that is really needed? My laptop runs fine now and I have no trouble with the internet speed or running programs. I don't have a system image but I do keep copies of important files like pictures, music, and documents on flash drives so if I did need to reset or re-install Windows that would not be a problem. The Avast Cleanup scan said I have some 200 or so broken registry files, which is what prompted me to think about resetting Windows.

Thanks for any input on this.

Cpt. Holly

My advice would be to test them in a virtual machine, or second computer where you can do a clean install if something goes wrong. Why experiment on your daily driver?
 

Captain Holly

Level 1
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Jan 23, 2021
45
Well, I don't have a VM but I do have another laptop I can use if something goes wrong with my main one. The problem I had with Revo and Avast may have been because I use the free version. Avast is a good AV but a few weeks ago I got tired of their upsells and offers and scans that did not do anything other than try to get me to use the paid version so I went back to Windows Security with Configure Defender set on High, also using Edge Chromium with Smart Screen, Webmail Adblocker and UBO on default settings. I have had no trouble with this setup so far and will keep it this way unless MS has any serious problems with Windows Security in the future. For now and the forseeable future I am learning to put my trust in MS and my own common sense/safe surfing habits.

C.H.
 
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