Depending on your browser version and OS, Firefox or Sea Monkey may hang, crash, or simply fail to start because of a problematic plugin.
If possible, visit Mozilla's Plugin Check page with another browser that Plugin Check supports (e.g., Safari or Opera) to help identify installed plugins.
Some very common issues are listed between step 3 and 4. Plugins allow viewing of various content types, e.g. In some cases, plugins are installed manually and also require a manual update.
The Mc Afee product installed right after Adobe finished.
A few days later, I finally got around to trying it out.
Note: The Firefox Software Update feature does not update installed plugins.
See the Adobe Security bulletins and advisories page for information about security and stability issues affecting Adobe Flash Player and other Adobe products.