Problem

SmartFTP takes a long time to start.

Solution

Favorites

Reduce the number of favorites:

1. Select the Tools tab. Click on Edit Favorites
2. Delete all favorites you don't have a need for anymore.

Cache and Cache settings

Delete the cache and adjust the cache settings:

1. Go to the menu: File - Settings
2. Go to the Connection - Cache dialog
3. Click on the Empty Cache button
4. Set the Cache Expiration setting to Every time the application is closed 

Close Browsers

Close all the browser windows (Local Browser and Remote Browsers) you don't need.

Reset Registry

If the solutions above did not bring the desired result you can delete all data stored in the registry:
KB: How To delete all registry settings