Your Mac doesn’t work well after you’ve installed macOS High Sierra? Or something went wrong during the installation? One of the easiest ways to fix such issues is reinstalling the operating system. Don’t worry; it won’t affect your files, data, apps, user settings, etc. Only a fresh copy of macOS High Sierra will be installed on your Mac again.

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Please note that if you need to remove the data and reset your Mac to factory settings, go for clean install macOS High Sierra. A clean install will delete everything associated with your profile, all your files, and documents, while the reinstall will not.

Open Launchpad by clicking on it in the Dock or from the Applications folder. If you don’t see the app that you want to remove on Launchpad, type its name on the search field. Press and hold the Option key, or click and hold on any apps until the icons start to wiggle. Click on the delete icon on the app that you want to delete. The High Sierra installer suddenly appeared in the Applications folder, and was NOT directly requested through the App Store (that Mac user account does not have local access to the App Store app). The High Sierra installer downloaded because it was allowed by the settings in the App Store pref pane. Java is one of the most confusing and frustrating add-ons for Mac and here we show you the easiest way to uninstall Java from El Capitan, Sierra and High Sierra. The truth is, there’s actually no way to fully remove Java from Mac but you can easily completely disable it. The built-in Storage Management application should allow you to find the item in the Applications panel and you can delete it from there. I personally found right-clicking on the item and selecting Delete to be more responsive than selecting it and using the button. Accessible on Sierra and later by: Apple icon About this Mac; Storage tab.

Once you’ve decided that you want to keep all your data intact, take advantage of our comprehensive guide on how to reinstall macOS High Sierra. But before you start, you have to prepare your Mac for the process.

Before You Begin: Back Up Your Data

Although the process of reinstalling is safe, it is still recommended to back up your data. Should something go wrong, you’ll be able to restore all necessary files easily.

There are a few incredibly easy ways to back up the files, documents, applications, etc. So, you can choose the most convenient one for you. One of the possible Mac backup solutions built into macOS is Time Machine. It allows frequent automatic backups. Surely, you can use iCloud, Dropbox, or any other external storage to back up essential data.

Before reinstalling the macOS High Sierra, you might also need to clean the system junk. And not the system junk alone, but also gigabytes of other unwanted files like app leftovers, browser extensions, etc. You don’t want to reinstall the operating system with all the clutter it contains, do you? You can clean up your Mac manually, but using an app like CleanMyMac X will save you tons of time. It will scan the system and safely remove all junk in a matter of minutes.

Once you’ve backed up your files and cleaned your Mac, you’re ready to reinstall macOS High Sierra.

A Step-By-Step Guide to Reinstall macOS High Sierra

Here’s how you can reinstall the macOS High Sierra and keep all files and user settings.

• Back up your Mac before you begin (just make sure you didn’t forget to do it).
• Click the Apple icon in the top left corner of your screen and choose Restart from the menu.

• Use the combination of Command and R keys; you’ll see the macOS Utilities window.
• Pick Reinstall macOS.

• Click Continue.
• Select your hard drive (this is usually Macintosh HD).

• Click Install and complete the process.

That’s it! As you see, reinstallation is not a difficult process, and it has an obvious advantage — it keeps all your data and configurations untouched. Now you can enjoy the new exciting features of macOS High Sierra, like faster Safari and better graphics.

However, if you don’t like the new version of macOS, don’t let it give you a bad time. You can always downgrade to Sierra. But before turning to such radical measures, try to reinstall the macOS High Sierra. Probably it will resolve all the issues.

We hope you found this article helpful. Have a nice day, and stay tuned!

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How to remove 'Your OS High Sierra Is Infected With (3) Viruses!' from Mac?

What is 'Your OS High Sierra Is Infected With (3) Viruses!'?

Fake virus alert messages such as 'Your OS High Sierra Is Infected With (3) Viruses!' usually appear only on untrustworthy, deceptive websites. Most users arrive at these websites unintentionally - they are redirected to them by potentially unwanted applications (PUAs). Typically, these apps infiltrate systems without users' consent. Once installed, they cause redirects to other untrustworthy websites [similar to the one that displays the 'Your OS High Sierra Is Infected With (3) Viruses!' fake message]. PUAs also deliver ads and collect data.

According to the 'Your OS High Sierra Is Infected With (3) Viruses!' error, your Mac computer is infected with three viruses (this number can vary). In this case, the message states that a 'security check' found two malware infections and one spyware/phishing program, and that immediate removal is required, otherwise you might lose your apps, photos, and other files, and put banking and other personal information at risk. The people behind these fake messages are usually scammers who trick people into downloading (and purchasing) software, paying money for their services, and so on. At time of research, scammers were promoting the Mac Cleanup Pro application that can supposedly fix all of the issues indicated, remove viruses, and so on. Once installed, the Mac Cleanup Pro tool will find even more issues than the 'initial scan' (security check found two malware infections and one spyware/phishing program). In any case, to use this application, you will have to pay for it. We do not recommend that you purchase this app or use it. The best solution is simply to ignore the 'Your OS High Sierra Is Infected With (3) Viruses!' fake virus alert message. Close the deceptive website that displays it and do not visit it again. If you cannot close it normally, close the entire browser using Activity Monitor or simply restart your computer. Do not restore the previously closed session, since this will opens the same deceptive website that originally displayed this fake message, or another dubious site.

Unwanted applications deliver ads and gather data. PUAs deliver banners, coupons, surveys and other similar ads that are displayed via tools that enable placement of third party graphical content on any site. These can be very annoying since, when displayed, they conceal underlying content of any visited website. Furthermore, they often lead to untrustworthy websites or run scripts designed to download unwanted applications. These unwanted apps are often categorized as information tracking apps. PUAs collect browsing-related data such as IP addresses, keystrokes, search queries, URLs of visited websites, etc. They also collect personal and sensitive details. Developers of these apps share the collected data with third parties (perhaps cyber criminals) who misuse it to generate revenue. Installed PUAs can thus lead to problems relating to privacy, and browsing safety. Some users might be forced having their identities stolen.

Scammers use a number of fake messages - usually fake virus alerts, fake errors, and so on. All are displayed on untrustworthy websites. Examples of similar fake messages are Your Computer Was Locked, Mac OS Support Alert, Spyware Were Found On Your Mac, and Error FXX000. These fake messages often trick people into purchasing unnecessary products or paying for services provided by scammers who claim to be 'official technicians'. All potentially unwanted applications are very similar. Developers promote them as useful tools, however, they are used to trick people into downloading unwanted apps. Generally, PUAs provide none of the functionality promised. They generate revenue for their developers and often cause various problems.

How did potentially unwanted applications install on my computer?

Potentially unwanted apps can sometimes be downloaded from their official websites, however, most users install them through intrusive advertisements or when software developers use the so-called 'bundling' method. Bundling is a deceptive marketing method used to install unwanted applications with regular software. Users are often tricked into installing them, since information regarding their presence in set-ups is not properly disclosed. Unwanted applications are usually hidden in 'Custom', 'Advanced' and other similar parts of the installation processes. Careless behaviour (skipping installation steps) often usually leads to unintentional installations of PUAs. Clicking intrusive ads without understanding the possible consequences might also cause inadvertent installations.

How to avoid installation of potentially unwanted applications?

Download software from official, trustworthy sources, and using direct links only. Avoid using third party software downloaders/installers, torrents or other similar sources. Do not finish any installation without checking the available 'Advanced'/Custom' and other sections/settings. Opt-out of any unwanted offers to install additional software, and only then finish the installation. Untrustworthy ads may seem legitimate, however, once clicked, they often redirect users to untrustworthy websites (gambling, pornography, adult dating, etc.). If you encounter these ads, check for unknown/unwanted plug-ins, add-ons, and extensions installed on your browser. Also look for unwanted programs installed on your computer. Remove unwanted entries immediately. If your computer is already infected with PUAs, we recommend running a scan with Combo Cleaner Antivirus for macOS to automatically eliminate them.

Text presented in 'Your OS High Sierra Is Infected With (3) Viruses!' scam website:

Your OS High Sierra is infected with (3) viruses!
Your OS High Sierra is infected with (3) viruses. Our security check found traces of 2 malware and 1 phishing/spyware. System damage: 28.1% - Immediate removal required!
The immediate removal of the viruses is required to prevent further system damage, loss of Apps, Photos or other files. Traces of 1 phishing/spyware were found on Your OS High Sierra with.
Personal and banking information are at risk.
To avoid more damage click on 'Scan Now' immediately. Our deep scan will provide help immediately!
4 minutes and seconds 54 remaining before damage is permanent.

Appearance of 'Your OS High Sierra Is Infected With (3) Viruses!' scam (GIF):

Screenshot of the installer of app (Mac Cleanup Pro) promoted by scammers:

Screenshot of the app (Mac Cleanup Pro) promoted by scammers:

Instant automatic Mac malware removal:Manual threat removal might be a lengthy and complicated process that requires advanced computer skills. Combo Cleaner is a professional automatic malware removal tool that is recommended to get rid of Mac malware. Download it by clicking the button below:
▼ DOWNLOAD Combo Cleaner for MacBy downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. To use full-featured product, you have to purchase a license for Combo Cleaner. Limited three days free trial available.

Quick menu:

• STEP 1. Remove PUA related files and folders from OSX.
• STEP 2. Remove rogue extensions from Safari.
• STEP 3. Remove rogue add-ons from Google Chrome.
• STEP 4. Remove potentially unwanted plug-ins from Mozilla Firefox.

Video showing how to remove potentially unwanted apps distributed by 'Your OS High Sierra is infected with 3 viruses':

Potentially unwanted applications removal:

Remove potentially unwanted applications from your 'Applications' folder:

Click the Finder icon. In the Finder window, select 'Applications'. In the applications folder, look for 'MPlayerX', 'NicePlayer', or other suspicious applications and drag them to the Trash. After removing the potentially unwanted application(s) that cause online ads, scan your Mac for any remaining unwanted components.

Combo Cleaner checks if your computer is infected with malware. To use full-featured product, you have to purchase a license for Combo Cleaner. Limited three days free trial available.

Remove 'your os high siera is infected with (3) viruses!' virus related files and folders:

Click the Finder icon, from the menu bar. Choose Go, and click Go to Folder...

Check for adware-generated files in the /Library/LaunchAgents folder:

In the Go to Folder... bar, type: /Library/LaunchAgents

In the “LaunchAgents” folder, look for any recently-added suspicious files and move them to the Trash. Examples of files generated by adware - “installmac.AppRemoval.plist”, “myppes.download.plist”, “mykotlerino.ltvbit.plist”, “kuklorest.update.plist”, etc. Adware commonly installs several files with the same string.

Check for adware generated files in the /Library/Application Support folder:

In the Go to Folder... bar, type: /Library/Application Support

In the “Application Support” folder, look for any recently-added suspicious folders. For example, “MplayerX” or “NicePlayer”, and move these folders to the Trash.

Check for adware-generated files in the ~/Library/LaunchAgents folder:

In the Go to Folder bar, type: ~/Library/LaunchAgents

In the “LaunchAgents” folder, look for any recently-added suspicious files and move them to the Trash. Examples of files generated by adware - “installmac.AppRemoval.plist”, “myppes.download.plist”, “mykotlerino.ltvbit.plist”, “kuklorest.update.plist”, etc. Adware commonly installs several files with the same string.

Check for adware-generated files in the /Library/LaunchDaemons folder:

In the Go to Folder... bar, type: /Library/LaunchDaemons

In the “LaunchDaemons” folder, look for recently-added suspicious files. For example “com.aoudad.net-preferences.plist”, “com.myppes.net-preferences.plist”, 'com.kuklorest.net-preferences.plist”, “com.avickUpd.plist”, etc., and move them to the Trash.

Scan your Mac with Combo Cleaner:

If you have followed all the steps in the correct order you Mac should be clean of infections. To be sure your system is not infected run a scan with Combo Cleaner Antivirus. Download it HERE. After downloading the file double click combocleaner.dmg installer, in the opened window drag and drop Combo Cleaner icon on top of the Applications icon. Now open your launchpad and click on the Combo Cleaner icon. Wait until Combo Cleaner updates it's virus definition database and click 'Start Combo Scan' button.

Combo Cleaner will scan your Mac for malware infections. If the antivirus scan displays 'no threats found' - this means that you can continue with the removal guide, otherwise it's recommended to remove any found infections before continuing.

After removing files and folders generated by the adware, continue to remove rogue extensions from your Internet browsers.

'Your OS High Siera Is Infected With (3) Viruses!' virus removal from Internet browsers:

Remove malicious extensions from Safari:

Remove 'your os high siera is infected with (3) viruses!' virus related Safari extensions:

Open Safari browser, from the menu bar, select 'Safari' and click 'Preferences...'.

In the preferences window, select 'Extensions' and look for any recently-installed suspicious extensions. When located, click the 'Uninstall' button next to it/them. Note that you can safely uninstall all extensions from your Safari browser - none are crucial for normal browser operation.

• If you continue to have problems with browser redirects and unwanted advertisements - Reset Safari.

Remove malicious plug-ins from Mozilla Firefox:

Remove 'your os high siera is infected with (3) viruses!' virus related Mozilla Firefox add-ons:

Open your Mozilla Firefox browser. At the top right corner of the screen, click the 'Open Menu' (three horizontal lines) button. From the opened menu, choose 'Add-ons'.

Choose the 'Extensions' tab and look for any recently-installed suspicious add-ons. When located, click the 'Remove' button next to it/them. Note that you can safely uninstall all extensions from your Mozilla Firefox browser - none are crucial for normal browser operation.

• If you continue to have problems with browser redirects and unwanted advertisements - Reset Mozilla Firefox.

How To Delete Apps On Macbook High Sierra

Remove malicious extensions from Google Chrome:

Remove 'your os high siera is infected with (3) viruses!' virus related Google Chrome add-ons:

Open Google Chrome and click the 'Chrome menu' (three horizontal lines) button located in the top-right corner of the browser window. From the drop-down menu, choose 'More Tools' and select 'Extensions'.

Mac How To Uninstall Applications

In the 'Extensions' window, look for any recently-installed suspicious add-ons. When located, click the 'Trash' button next to it/them. Note that you can safely uninstall all extensions from your Google Chrome browser - none are crucial for normal browser operation.

How To Uninstall Software On Mac

• If you continue to have problems with browser redirects and unwanted advertisements - Reset Google Chrome.