Gatekeeper

Question

Gatekeeper ruined my dashboard development completely. No security certificate for Dashboard Widgets. Here are some tips to fix this:
“App can’t be opened because it is from an unidentified developer”
Since OS X Mountain Lion, the Mac defaults to preventing applications from unidentified developers or sources from being launched. You’ll discover the message in OS X 10.8 when you try to launch a Mac app that didn’t come from a verified source or from the Mac App Store, and you’ll get an alert dialog that says “[App name] can’t be opened because it is from an unidentified developer”.
This new security feature is called GateKeeper, and it doesn’t mean you can’t run those unverified apps on the Mac, you just have to either temporarily skirt the security blanket of GateKeeper, or turn off the app limitations entirely.
Temporarily Get Around “App Can’t Be Opened” Gatekeeper Alert Message
This is probably the best option for most users, since it maintains some security:
Right-click (or control-click) the application in question and choose “Open”
Click the “Open” button at the next dialog warning to launch the app anyway
You can do this with any third party app that gives you this warning dialog and open it anyway.
If you get tired of constantly right-clicking apps to open them, return to pre-Mountain Lion levels of app security by turning off Gatekeepers app verification completely.
Disable GateKeeper’s Unidentified App Developer Prevention Completely
This is generally best for advanced users who know what apps to trust and not to trust:
Launch System Preferences from the Apple  menu
Choose “Security & Privacy” and then click the “General” tab, followed by clicking the lock icon in the corner to unlock the settings
Look for “Allow applications downloaded from:” and choose “Anywhere”
Accept the security warning and allow
You can now launch any app from any location or developer
Bypass Gatekeeper in OS X Mavericks with Security Preferences
Gatekeeper is an application level security feature on the Mac that aims to prevent unauthorized and unidentified apps from being launched in OS X, thereby preventing potential security problems like exploits or trojans from running on a Mac. The feature is most often encountered when an app has been downloaded from the web, and upon attempting to launch the app a warning dialog will prompt the user with a message saying something along the lines of “This app can’t be opened because it is from an unidentified developer“. We’ve covered how you can get bypass that error message on a case-by-case basis by using the right-click “Open” trick, but the latest version of OS X brings another option which may be easier for some users to selectively launch apps and bypass Gatekeeper. This is advantageous because users can continue to retain the strict security preference of leaving Gatekeeper enabled and intact, which is generally recommended.
Bypass Gatekeeper App Launch Warnings from System Preferences
This solution is temporary, providing a per-application launch bypass. It does not disable Gatekeeper in OS X.
Attempt to launch the application inquestion, encountering the normal “can’t be opened” message, then click “OK”
Launch System Preferences by choosing it from the  Apple menu
Select the “Security & Privacy” control panel, and go to the “General” tab
Under the “Allow apps downloaded from:” look for the following message: “appname.app was blocked from opening because it is not from an identified developer.”
If you trust the application and want to launch it bypassing Gatekeeper, click “Open Anwyay”
If the “Open Anyway” option is not visible then you likely must unlock the security preferences by clicking the little padlock icon in the corner and entering an administrative password.
Choosing “Open Anyway” will launch the application in question directly from Security System Preferences, and you’ll be able to use it as normal. This approach is obviously slightly more time consuming than using the right-click Open trick, but it may be advantageous for certain users in select situations.
Gatekeeper is really aimed at protecting novice and average Mac users, while advanced OS X users who are more comfortable with things may find the warnings to be intrusive or annoying. If you don’t want to receive the warnings at all, you can simply disable Gatekeeper completely through the Security System Preferences by choosing “Anywhere” from the allow apps list.
This feature was first introduced to the Mac with OS X Mountain Lion, but the “Open Anyway” option inside the Security preferences is new with OS X Mavericks.

Answer 1

Gatekeeper ruined my dashboard development completely. No security certificate for Dashboard Widgets. Here are some tips to fix this:
“App can’t be opened because it is from an unidentified developer”
Since OS X Mountain Lion, the Mac defaults to preventing applications from unidentified developers or sources from being launched. You’ll discover the message in OS X 10.8 when you try to launch a Mac app that didn’t come from a verified source or from the Mac App Store, and you’ll get an alert dialog that says “[App name] can’t be opened because it is from an unidentified developer”.
This new security feature is called GateKeeper, and it doesn’t mean you can’t run those unverified apps on the Mac, you just have to either temporarily skirt the security blanket of GateKeeper, or turn off the app limitations entirely.
Temporarily Get Around “App Can’t Be Opened” Gatekeeper Alert Message
This is probably the best option for most users, since it maintains some security:
Right-click (or control-click) the application in question and choose “Open”
Click the “Open” button at the next dialog warning to launch the app anyway
You can do this with any third party app that gives you this warning dialog and open it anyway.
If you get tired of constantly right-clicking apps to open them, return to pre-Mountain Lion levels of app security by turning off Gatekeepers app verification completely.
Disable GateKeeper’s Unidentified App Developer Prevention Completely
This is generally best for advanced users who know what apps to trust and not to trust:
Launch System Preferences from the Apple  menu
Choose “Security & Privacy” and then click the “General” tab, followed by clicking the lock icon in the corner to unlock the settings
Look for “Allow applications downloaded from:” and choose “Anywhere”
Accept the security warning and allow
You can now launch any app from any location or developer
Bypass Gatekeeper in OS X Mavericks with Security Preferences
Gatekeeper is an application level security feature on the Mac that aims to prevent unauthorized and unidentified apps from being launched in OS X, thereby preventing potential security problems like exploits or trojans from running on a Mac. The feature is most often encountered when an app has been downloaded from the web, and upon attempting to launch the app a warning dialog will prompt the user with a message saying something along the lines of “This app can’t be opened because it is from an unidentified developer“. We’ve covered how you can get bypass that error message on a case-by-case basis by using the right-click “Open” trick, but the latest version of OS X brings another option which may be easier for some users to selectively launch apps and bypass Gatekeeper. This is advantageous because users can continue to retain the strict security preference of leaving Gatekeeper enabled and intact, which is generally recommended.
Bypass Gatekeeper App Launch Warnings from System Preferences
This solution is temporary, providing a per-application launch bypass. It does not disable Gatekeeper in OS X.
Attempt to launch the application inquestion, encountering the normal “can’t be opened” message, then click “OK”
Launch System Preferences by choosing it from the  Apple menu
Select the “Security & Privacy” control panel, and go to the “General” tab
Under the “Allow apps downloaded from:” look for the following message: “appname.app was blocked from opening because it is not from an identified developer.”
If you trust the application and want to launch it bypassing Gatekeeper, click “Open Anwyay”
If the “Open Anyway” option is not visible then you likely must unlock the security preferences by clicking the little padlock icon in the corner and entering an administrative password.
Choosing “Open Anyway” will launch the application in question directly from Security System Preferences, and you’ll be able to use it as normal. This approach is obviously slightly more time consuming than using the right-click Open trick, but it may be advantageous for certain users in select situations.
Gatekeeper is really aimed at protecting novice and average Mac users, while advanced OS X users who are more comfortable with things may find the warnings to be intrusive or annoying. If you don’t want to receive the warnings at all, you can simply disable Gatekeeper completely through the Security System Preferences by choosing “Anywhere” from the allow apps list.
This feature was first introduced to the Mac with OS X Mountain Lion, but the “Open Anyway” option inside the Security preferences is new with OS X Mavericks.