All my troops have disappeared
Solution 1:
This is caused by a cache error in the game. Usually re-opening the game fixes it, but if not go to Settings > Applications > Application Manager > Clash of Clans > Storage > Clear Cache. This works for Android devices, so if you use an Apple device just navigate to the application in your settings.
If you can't clear the cache/are unable to just restart your phone (or if it doesn't work), re-install the app.
Solution 2:
Just to add on to what Crafter, said since I've seen this myself. I've found that going between the original base and the builder base and back to home makes everything reappear. As to avoid clearing caches and doing a quick fix.
Granted the troops are still there and the defense buildings are still fully functional.