Fresh download -> Error: "MuleStudio.app is damaged and can't be opened."

Question

Trying to install Mulesoft's developer studio. Did a fresh download of MuleStudio-for-macosx-64bit-3.5.0-201312091746.zip from http://www.mulesoft.org/thank-you-downloading-mule-studio-mac and unzipped, can't run the MuleSoft.app file.

Only options are to Cancel or "Move to Trash"

Things I've checked:

• The checksum is correct: 42433b0ed8e82e969111799f7a2d136c

• I tried the Control-Click to open, same problem.

• Tried re-unzipping it.

• Java 7, 1.7.0_45 64bit

• Mac OS X Mavericks 10.9.2 and up to date

Answer 1

The error message is from the Gatekeeper security system built into OS X. According to the help page, this particular message can appear if the application package has been tampered with (e.g. its signature no longer matches the developer's certificate).

This may be harmless, or it may be an indication that the package has been hijacked and contains malicious code. The former is probably more likely, but I would email the developers before opening the package, just to be sure.

The help page for Gatekeeper gives more details, including disabling the feature if you'd like to go ahead and launch the app anyway.