This is not a troubleshooting guide for merely slow verifications or for those who are simply impatient, this is only for cases where “verifying” process is completely halted and not working at all, thereby preventing the intended installer from running.
Note: the “Verifying” process for packages, installers, and updates can take a while on any Mac. If you ever run into the package stuck on verifying issue within Mac OS X, we’ll show you how to fix the problem and get the package update to install on the Mac anyway. This is a strange issue that can cause some alarm, because it can happen with both third party packages and installers, as well as updates and packages that come directly from Apple. The effect is the package or installer won’t run as it never completes verification, making it impossible to install. Mac users may find that a system update, installer, or package (pkg) can get completely stuck in a verification sequence, with a pop-up alert that says “Verifying ‘name.pkg’…” while showing the Gatekeeper icon and a progress bar that never updates.
