I follow suggestions on 2.8.2 very slow to launch on OS X 10.6.8 on GIMP on OS X suggest to turn off network. It does help to speed up GIMP but LibreOffice.
Turn Off Gatekeeper for First-Time Launch
After reinstall them several times, it seems you have to Allow applications downloaded from “Anywhere” in Security & Privacy for first-time launch. No need to disable network. Fix the “App can’t be opened because it is from an unidentified developer” Error in Mac OS X on OSX Daily provides a step-by-step instruction.
After launching successfully, you may switch back to “Mac App Store and identified developers” to keep you safe. They will be fine.
Update on 2017/5/17
On macOS Sierra, right click on the installer and choose [Open With] → [Installer (default)]. A dialog with [open] button will be launch. Now you may bypass Gatekeeper.
These applications can’t be opened because they are from an unidentified developer. But even choose to ignore warning, I still cannot launch them. Sometimes, they just stuck on verifying without any warning dialog. It is very confusing.
- GIMP on OS X: 2.8.2 very slow to launch on OS X 10.6.8
- OSX Daily: Bypass Gatekeeper in OS X Mavericks with Security Preferences
- OSX Daily: Fix the “App can’t be opened because it is from an unidentified developer” Error in Mac OS X
- Wiki: Mac Mini: 4 Unibody Mac Mini
- Wiki: OS X: 5.12 Version 10.10: “Yosemite”