This article explains the rationale behind a blocked plug-in on Mac and provides a workaround for the error, including a way to remove the misbehaving app.
Plug-ins are intended to make sure a system component, such as a web browser, supports certain features or types of content provided by websites and other modern electronic services. This is an important prerequisite for delivering a proper user experience, but with the caveat that these enhancements largely have a third-party nature and may become a source of security issues. An error on Mac saying “Blocked Plug-in” typically means that the system has prevented a specific plug-in from running. Most reports regarding this issue are associated with Adobe software, including Flash Player and Acrobat Reader. For instance, the alert may occur when a user tries to open an email link in Safari leading to a PDF document. The file preview turns out to be a no-go in this case as the browser displays a black screen with the above-mentioned message in the center. Incidentally, this can be a cross-browser issue and hold true for Chrome and Firefox as well.
One more scenario that falls under the same category is when a Mac user goes to a website that relies on Adobe Flash Player to interact with the visitors. A common situation involves watching multimedia or playing an in-page game. The “Blocked Plug-in” error may show up alongside a notification saying that the content requires the latest version of the Flash Player. Why would Apple pull the plug on a plug-in (pardon the linguistic redundancy)? In the case of Flash, things are fairly clear. This software has gained notoriety for being crammed up with vulnerabilities. Although Adobe is releasing patches off and on, computers running it may stay susceptible to cybercriminals’ attacks for months. Arbitrary code execution and data theft are among the biggest issues stemming from these imperfections. Moreover, the vendor is rumored to plan on ending support of Flash Player in 2020 and it will be eventually disabled from major web browsers by default. As a matter of fact, Apple has already done it since Safari 10, but users can still turn on the plug-in if they need it.
In addition to the obvious legit causes for macOS to block a plug-in, there is a shadier course of action that involves the error messages in question. Malware distributors might try to ambush a user by misreporting a bug of that kind. To execute this hoax, perpetrators use a potentially unwanted application (PUA) that hijacks the victim’s web browser and either forwards the traffic to sketchy sites or triggers misleading popup warnings. This type of a malvertising campaign is accompanied by “Missing Plug-in” or “Blocked Plug-in” alerts. Unlike valid system notifications, these ones will typically include a button to download the latest build of the “enhancement” tool. However, instead of installing the software, this routine results in depositing a malicious app such as adware that will embed sponsored links and display ads across the visited web pages. Scareware is another common form of harmful code doing the rounds this way.
If “Blocked Plug-in” errors are actually shown by macOS for security reasons or to maintain system stability, there are several things that should sort it out. Before moving on to the troubleshooting, it’s worth pointing out that the benign instance of disabling of a random plug-in usually occurs right after an upgrade to a new system version that introduces a change in handling third-party applications. Let’s now zoom back into the repair. Here are a few techniques every effected Mac user should try first:
- Update the plug-in. First things first, the applet may have been blocked because it’s way out of date. If so, the starting point of the fix is to determine which plug-in cannot be launched. If the error pops up when you are trying to preview a PDF file received over email, then go to get.adobe.com and download the newest iteration of Acrobat Reader. If it’s a Flash Player issue, then install the most recent release of the program from the above site.
- Make sure Safari is up to date. Note that the “Blocked Plug-in” alert is mostly a Safari issue. If you are using macOS Catalina, then you already have the latest version of the browser and you can skip this step. For earlier versions of the operating system, click the App Store icon in the Dock, go to the Updates tab, and check if there is a newer version of Safari or whatever browser is acting up. Apply the update if available.
- Re-enable the plug-in manually. Expand the Safari menu and select Preferences. Click the Websites tab (on older macOS versions, go to Security tab). The bottom part of the left-hand navigation bar reflects the list of installed plug-ins and their current status. Find the right entry and check the box next to it to enable the plug-in. You can configure the app to only run on specific sites, too.
If the above steps don’t rid you of the “Blocked Plug-in” error, chances are that it’s caused by malicious activity on your Mac. To address the predicament, you need to check the computer for unwanted code and remove it for good. The sections below will walk you through this process.
Blocked plug-in error redirect virus manual removal for Mac
The steps listed below will walk you through the removal of the malicious application. Be sure to follow the instructions in the order specified.
- Open up the Utilities folder as shown below
- Locate the Activity Monitor icon on the screen and double-click on it
- Under Activity Monitor, find a suspicious-looking process, select it, and click Quit Process
- A dialog should pop up, asking if you are sure you would like to quit the troublemaking process. Select the Force Quit option
- Click the Go button again, but this time select Applications on the list. Find the unwanted app on the interface, right-click on it and select Move to Trash. If user password is required, go ahead and enter it
- Now go to Apple Menu and pick the System Preferences option
- Select Accounts and click the Login Items button. The system will come up with the list of the items that launch when the computer is started up. Locate the potentially unwanted object there, select it, there and click on the “-“ button
Get rid of “Blocked Plug-in” alert in web browser on Mac
To begin with, settings for the web browser that got hit by the virus should be restored to their default values. The overview of steps for this procedure is as follows:
- Reset Safari
- Open the browser and go to Safari menu. Select Preferences in the drop-down list
- Once the Preferences screen appears, hit the Privacy tab at the top. Find the option that says Remove All Website Data and click on it
- The system will display a confirmation dialog that also includes a brief description of what the reset does. Specifically, you may be logged out of some services and encounter other changes of website behavior after the procedure. If you’re okay with that, go ahead and click the Remove Now button
- In order to selectively clear data generated by certain websites only, not all of them, hit the Details button under the Privacy section of Safari Preferences
- This feature will list all websites that have stored potentially sensitive data, including cache and cookies. Select the one, or ones, that might be causing trouble and click the appropriate button at the bottom (Remove or Remove All). Click the Done button to exit.
- Open the browser and go to Safari menu. Select Preferences in the drop-down list
- Reset Google Chrome
- Open Chrome, click the More (⁝) icon in the top right-hand part of the window, and select Settings in the drop-down
- When on the Settings pane, select Advanced
- Scroll down to the Reset settings section. Under the Restore settings to their original defaults option, click the Reset settings button
- Confirm the Chrome reset on a dialog that will pop up. When the procedure is completed, relaunch the browser and check it for malware activity.
- Reset Mozilla Firefox
- Open Firefox and select Help – Troubleshooting Information
- On the page that opened, click the Reset Firefox button
Get rid of “Blocked Plug-in” error using Combo Cleaner removal tool
The Mac maintenance and security app called Combo Cleaner is a one-stop tool to detect and remove “Blocked Plug-in” error virus virus. This technique has substantial benefits over manual cleanup, because the utility gets hourly virus definition updates and can accurately spot even the newest Mac infections.
Furthermore, the automatic solution will find the core files of the malware deep down the system structure, which might otherwise be a challenge to locate. Here’s a walkthrough to sort out the “Blocked Plug-in” error virus issue using Combo Cleaner:
- Download Combo Cleaner installer. When done, double-click the combocleaner.dmg file and follow the prompts to install the tool onto your Mac.
- Open the app from your Launchpad and let it run the update of malware signature database to make sure it can identify the latest threats.
- Click the Start Combo Scan button to check your Mac for malicious activity as well as performance issues.
- Examine the scan results. If the report says “No Threats”, then you are on the right track with the manual cleaning and can safely proceed to tidy up the web browser that may continue to act up due to the after-effects of the malware attack (see instructions above).
- In case Combo Cleaner has detected malicious code, click the Remove Selected Items button and have the utility remove “Blocked Plug-in” error virus threat along with any other viruses, PUPs (potentially unwanted programs), or junk files that don’t belong on your Mac.
- Once you have made doubly sure that the malicious app is uninstalled, the browser-level troubleshooting might still be on your to-do list. If your preferred browser is affected, resort to the previous section of this tutorial to revert to hassle-free web surfing.