[Solved] How to Fix Error Plugin Container for Firefox has stopped working

Problem: How can I fix FireFox error “Plugin Container for Firefox has stopped working”? Plugin Container or plugin-container.exe for Firefox is the feature to avoid crashes caused by plugins. Perform following steps to fix Plugin Container for Firefox has stopped working problem.

Plugin Container for Firefox has stopped working

Solution 1: Update Shockwave Flash Player

Step 1: Open Mozilla Firefox browser.

Step 2: Go to Tools > Add-ons > Plugins > Update Now, you will redirected to Adobe Flash Player site or Shockwave Flash.

Step 3: At the Adobe Flash Player site, make sure you disable the optional offers at the middle of the browser window which would install McAfee tools on your Pc and click Install now button.

Step 4: Execute the file and wait for installation to complete.

Step 5: Restart your computer afterwards and check to see if the error still appears.

Step 6: If Error happen during Flash Player installation process, perform Flash Player uninstall using Uninstaller tool from Adobe, and deleting all files and folders in the follwing path after Flash Player uninstallation completed:
%appdata%\Adobe\Flash Player
%appdata%\Macromedia\Flash Player

Restart computer and try installing the Flash Player using the info above.

Solution 2: Broken Xmarks Add-on

Step 1: Open Mozilla Firefox browser.

Step 2: Click the blue Xmarks icon at the top right side of the window and choose Xmarks Settings option.

Step 3: If Xmarks is not currently running, you can open the settings via Menu > Add-ons or You can type in about:addons in the address bar.

Step 4: Locate Xmarks add-on > Options button.

Step 5: Navigate to Advanced > Repair.

Step 6: Follow the prompts which will appear on screen and restart browser afterwards.

Solution 3: Update Firefox

Step 1: Open Mozilla Firefox browser.

Step 2: Click on menu > Help section and choose About Firefox option.

Step 3: Browser will start checking for updates and downloading them immediately if there are any. When the download process is complete, you will be able to see the Restart to update Firefox button so click on it.

Solution 4: Disable Adobe Flash Protected Mode

Step 1: Open Mozilla Firefox browser.

Step 2: Click on menu > Add-Ons option.

Step 3: Click on the Plugins option at the right pane of the screen to view the full list of plugins installed.

Step 4: Click on Options next to the Shockwave Flash entry and uncheck Enable Adobe Flash protected mode.

Step 5: For Windows 64-bit users: Locate a file named mms.cfg in C:\Windows\SysWOW64\Macromed\Flash\mms.cfg, or create a new text file using Notepad and Save the file as mms.cfg then set the Save as type option to All types. Open mms.cfg file and put the following line at the bottom: ProtectedMode=0. Save the changes and close Notepad.

Solution 5: Disable Hardware Acceleration

Step 1: Open Mozilla Firefox browser.

Step 2: Click on menu > Options.

Step 3: Scroll down to Performance section and uncheck Use recommended performance settings checkbox in order to gain access to the Use hardware acceleration when possible entry. Uncheck the check box next to it as well and close the menu.

Reference: Mozilla FireFox Support: How can I fix a “Plugin Container for Firefox has stopped working” error?