it was discussed several times in this forum, so I might have a solution for all, who have problems running Gearbox properly on OSX Yosemite (10.10.1).
1. Remove all (!) Line6 files and drivers from your Mac according to the Line 6 advice pdf from Line6Tony (http://line6.com/support/topic/9951-pod-x3-live-osx-yosemite/?p=71889) and AFTER THIS remove Line 6 device (i.e. X3 Live), restart your computer.
2. Download Gearbox lastest version
3. Doubleklick dmg-file
4. Open the package (right mouse klick on the package GearBox.mpkg) the left klick on Package... in context menu)
5. Open folder "Contents" and then folder "Packages"
6. Then install the packages manually IN FOLLOWING ORDER (IMPORTANT!)
- GearBox AU Plugin.pkg
- Gearbox RTAS Plugin.pkg
DO NOT INSTALL GearBox.pkg YET!
- Line6 Audio Driver.pkg
- Line 6 Audio-Midi Pref.pkg IS NOT INSTALLABLE - BUT IT DOESN'T MATTER!
- Line 6 Driver Uninstaller.pkg
DO NOT INSTALL Line 6 Monkey.pkg YET!
- Line6 TWX Framework.pkg IS NOT INSTALLABLE - BUT IT DOESN'T MATTER!
- Line 6 TWGX Framework.pkg
7. After doing that, install Line6 GearBox.pkg
8. Restart now (not earlier!)
9. Connect Device
10. Start GearBox. It will open without any errors!
You're ready to go.
After that, you can install Line6Monkey if you want, but:
1. Do not use the package delivered with Gearbox, download latest Version from Line6 Support
2. After Installation DO NOT UPDATE ANY DRIVER! It will work properly withoui any updates
I tried it on two computers (Imac 27" end 2013, and MacBookPro Mid 2011, both with Yosemite).