- Why am I getting "Unable to launch" error on PC?
In many cases, an old launch.jnlp file will be saved in your cache. While clicking on 'Launch' this will be invoked instead of the new one. This is a known java issue and will hopefully be fixed soon. A temporary workaround will be,
- Windows 7: Goto Control Panel > Programs > Java > General > Temporary Internet Files > Settings and Uncheck 'Keep Temporary Files on my computer.
- Windows XP: Goto Settings > Control Panel > Java > General > Settings and Uncheck 'Keep Temporary Files on my computer.
- When I try to open CMT, I see the error CMT is damaged and can't be opened. You should move it to the trash.
This is a result of Mountain Lion's new Gatekeeper. To run CMT you will need to temporarily disable Gatekeeper.
- Open System Preferences and select Security & Privacy
- Under the General tab, select Anywhere for Allow applications downloaded from
- Open CMT
- If you wish, you can now reactivate Gatekeeper (CMT should open without error from now on)