If you installed a plug-in and notice that Safari runs more slowly, quits unexpectedly, won’t download files, or has other problems, the plug-in may be the problem.
You can quickly disable or enable a plug-in. This is an easy way to check if the plug-in is causing problems.
Choose Safari > Preferences, click Security, click Plug-in Settings next to Allow Plug-ins.
Do either of the following:
Disable a plug-in: Deselect the checkbox to the left of the plug-in name.
Enable a plug-in: Select the checkbox to the left of the plug-in name.
You can allow a plug-in for some websites and block it for others.
Choose Safari > Preferences, click Security, then click Plug-in Settings next to Allow Plug-ins.
Select the plug-in you want to disable on the far left, then click each pop-up menu on the right and choose Block.
For some plug-ins, you see pop-up menus for different websites, and you can choose to block each one individually. Use the “When visiting other websites” pop-up menu to block all other websites that don’t have individual settings.
If the problem is fixed, contact the developer of the plug-in to see if there’s a newer version.