E: Could not get a lock / var / lib / dpkg / lock-frontend. Maintained by process 12657 (synaptic) N: Please note that removing the lock file is not a solution and may harm your system. E: Failed to get the dpkg interface lock (/ var / lib / dpkg / lock-frontend). Is there another process using it?
This has nothing to do with Geany, it is a basic function of the system that you can't run two install processes at the same time.