Windows defender error 0x800700AA, service can not be started comes when the user is trying to run Windows defender scan on their system.
This kind of behavior happens for two reasons mostly, third-party application conflict or corrupted system files.
In this article, we will tackle both scenarios and provide you with solutions in both cases.
In this rare scenario when Windows defender can not start scan due to conflict with installed service or application in the system solution is quite simple. Restart your PC into safe mode and run the scan from there. In a safe mode environment, minimum drivers and services are only loaded eliminating any conflicts that might occur when everything is booted. If Windows defender can not run the scan in safe mode and you get the same 0x800700AA error then you can eliminate application conflict as a reason and move to the next solution which will tackle corrupted system files. If you, however, managed to run a scan then you have a rare third-party application conflict, you can boot normally into windows and try to eliminate one by one to see which one is causing the issue. The safest bet would be to start with security software because most of the time that is what causes conflicts in running services and applications.
If the previous solution has not provided you with results then you have system file corruption that needs to be fixed. Move from one solution to another as presented below:
SFC scan is a built-in Windows tool for solving corrupted system files issues, it is fully automated and does not require from the user any kind of knowledge or information. To run it and scan the system do the following:
Press ⊞ WINDOWS + X to open the secret menu
Left-click on the command prompt (admin)
In command prompt type SFC /SCANNOW and press ENTER
Wait for the process to finish, do not interrupt it and once it is done, restart your computer
DISM scan is similar to SFC scan but it tackles different types of system file corruption and it is recommended to run it also after SFC has been completed. Please note that for DISM scan to be successful you will need a stable internet connection since DISM will replace corrupted files with new ones downloaded from Microsoft. To run it do the following:
Press ⊞ WINDOWS + X to open the secret menu
Left-click on the command prompt (admin)
inside command prompt type: exe /online /cleanup-image /scanhealth followed by ENTER, then type: Dism.exe /online /cleanup-image /restorehealth also followed with ENTER.
Leave scan to finish and reboot your PC
Error code 0x8007007b will present itself when Windows users are trying to activate Windows. You may try to activate it through the update and security option, but it is likely that you will receive the same error code. Error code 0x8007007b may be presented when Windows 7 and Windows 8.1 users try to upgrade and activate Windows 10 on their computer.
Common symptoms include:
There are multiple causes for the user to see this error code, including if a user is using volume-licensed media while installing a number of various Windows operating systems. This error may also be caused because the activation wizard cannot connect to a KMS host computer. It is likely that if the user has a volume-licensed form of media, they were likely given a MAK (multiple activation keys).
There are several ways to go about repairing error code 0x8007007b. It is important to try all of the methods, but if it is too difficult or you do not know what you are doing, please do contact a Windows repair technician. They will likely be able to fix the problem with ease.
When KMS activation is not used, and when there is not a KMS server, the product key type should then be changed to a MAK. For MSDN (Microsoft Developer Network) or TechNet, the SKUs that are listed on the media are generally volume-licensed media, and that means that the product key that is supplied is a Multiple Activation Key.
To change the KMS to a MAK, click Start, All Programs, Accessories, and then right-click on Command Prompt. Click Run as Administrator. If prompted for a password or confirmation, enter it now.
When the command prompt opens, type in the following command, and press enter after:
slmgr -ipk xxxxx-xxxxx-xxxxx-xxxxx (these x's are representative of the MAK product key).
While on the desktop, press the Windows key and R. The Run window should appear, and then you should enter the following command: Slui 3. Press Enter and then wait for the window to appear. This window will ask for the operating system activation product key. Enter the product key and then press the Activate button. Reboot the computer. Now the Error Code 0x8007007b should be gone.
Open the Command Prompt with access as administrator as mentioned previously. Enter the following command: sfc /scannow. The command will then complete its task. This will take a good bit of time, so leave the computer to do its work. The sfc must finish the scan. When the scan has finished, reboot the computer. Now you can check for activation. The error code should be gone.
This method for correction should be used when the network does have a KMS host computer setup, and the client is not able to locate the KMS host on the network to complete activation.
To verify that the computer does in fact have the KMS host installed. Click Start, All Programs, Accessories, and then right-click on Command Prompt. Run as administrator. If you are now prompted to enter a password or confirmation, do so. When the command prompt box comes up, type in the following command, and then press Enter: nxlookup -type=all_vlmcs._tcp>kms.txt
The command will generate a file, open this KMS file. The file will contain one or more entries. As a default, the KMS host server will dynamically register a DNS SRV server evidence once every 24 hours. In order to check the registry to ensure that this is happening, follow these steps:
If you wish to always have at your disposal a utility tool to fix these Windows 10 and other related issues when they do arise, download and install a powerful automated tool.
Easy Directions Finder is a browser extension developed by Mindspark Inc. for Google Chrome. This extension offers users quick access to popular websites for navigation and evens. While at first glance this might look useful, keep in mind that this extension has been marked as a Browser Hijacker by several anti-virus applications.
When installed EasyDirectionsFinder will record your browsing history, visited links, clicked URL-s, and viewed products. This data is later forwarded/sold to Mindspark's ad network and used to better target ads to users.
While browsing the internet with this extension installed (it does not have to be enabled) you will see additional injected ads, sponsored links, and pop-up ads throughout your browsing sessions. Due to its information mining behavior and aggressive ad injections, it is recommended to remove this extension from your computer.
Upon updating to Windows 10, some users might encounter a blinking or flashing desktop after logging in. This will result in a repetitive restarting of explorer or you won’t be able to make the start menu and shortcut keys work. In addition, the network icon might not appear in your taskbar as well. Other Windows 10 error messages include error code 0xc000021a.
Your blinking or flashing desktop after logging in might be the result of problems with the bushell.dll shell extension, which is a part of the Norton Security Suite. Another possible cause for this annoying problem is an issue with your display driver since not all systems will use the same display driver and will depend on what graphics card you use.
In fixing the bothersome blinking or flashing desktop after logging in problem, you can do a manual repair method to address the root problem. You need to be familiar with the Windows command line to successfully go through the process. However, if you are not knowledgeable or confident enough to do this on your own, it would be best to seek help from a professional. Or, you might want to consider using an automated tool to solve the issue.
You need to identify first what’s causing the blinking or flashing of your desktop after login to properly address the issue. The following methods can be done if your issue is caused by bushell.dll shell extension issue:
NOTE: Text input is most probably affected by the explorer restarts so you might need to repeatedly type some letters or to carefully input texts.
NOTE: You might need to download the latest Video Driver on a working computer. Save it in a thumb drive then copy and install it on your computer. If in case there is no native Windows 10 driver, you can also download the latest Windows 7 or Windows 8.1 video driver. Afterward, install it in compatibility mode.