Google is the default search engine in the Chrome web browser because both are Google products. However, malware or unwanted programs (PUP) can automatically transfer the default search engine from Google to Yahoo.
Here is how to delete Yahoo search engine and avoid trouble when you have to exchange many times.
Set your favorite search engine to do default
Chrome allows users to use different search engines, with default options including Bing, Duckduckgo, Yandex and Yahoo. First, check if your browser is using which search engines are the default. If it's Yahoo, you can change Chrome's default search engine and return Google.

- Click on three vertical dots in the upper right corner and choose Settings.
- Navigate to the tab Search Engine From the left bar.
- Click Manage Search Engines and Site Search.
- If Yahoo is set by the default, click on the three vertical dots Google and click Make default.
The transfer of the default search engine to Google will temporarily fix the problem. However, it can automatically return to the previous state after a few days. Therefore, in order to change this effect, you will have to delete Yahoo and other search engines.
Delete Yahoo's search engine from Chrome
In Chrome, you can delete Yahoo from the search engine list to minimize your browser's possibility that you will default to Yahoo again.

- Click on three vertical dots in the upper right corner and choose Settings.
- From the left bar, navigate to Search Engine.
- Click Manage Search Engines and Site Search.
- Click on the three dots right next to Yahoo.
- Press Delete.
In addition, you can delete all other search engines, except Chrome, from the list if they become the default option. After that, your browser cannot default to Yahoo again.
Determine and delete PUP programs
If Google's search engine is replaced by Yahoo, you should delete all unwanted programs (PUP) that can cause problems, especially programs related to Yahoo.
To do this, enter Control Panel in Windows Searchopen the Control Panel application and come to Programs and features. Here, look for any suspicious program that can be related to Yahoo, right -click on each program and choose Uninstall.

Running security check on computers
If no previous correction is effective, then it's time to check your computer to find the browser to be attacked or toxic files to be deleted. Run the Microsoft Defender virus to remove hidden files, potentially harmful.
Microsoft Defender will detect threats and notify you about their severity. If you find any malware or threat, delete them immediately. Depending on the amount of data on the system, the scan may take some time.
If you encounter this problem on MacOS, check your Macbook to find malware and delete any software you find.
There is no effective correction? Please reinstall Chrome!
As the last option, you can try to reinstall Chrome. First, remove Chrome settings and related files before reinstalling.
Windows users can refer to this article on how to uninstall the program in Windows, while MacOS users can refer to this guide on how to uninstall the program on the Mac.
After uninstalling Chrome according to these instructions, delete all the remaining files to make sure there are no garbage data left. Then, install the new Chrome copy.