If you upgrade to version 4.1.1.0 of base camp on a MAC, there is a problem if you have time machine back up. When time machine volume mounts base camp reads it and tries to index all
picture files located on that volume. This causes the app to hang. Only fix for now is to turn off
backups while in base camp.
Evidently this is not a new problem... See: https://forums.garmin.com/showthread.php?34496-Basecamp-4-1-1-for-MAC-hangs-when-Time-Machine-backing-up
I use a FireWire drive for time machine and never seen this issue.