Dropbox has a 'Selective Sync' feature which allows you to select only the folders you want to sync to your computer. The Selective Sync conflict may occur in future. Selective Sync conflict can occur when you choose not to sync a folder to your computer in your Selective Sync preferences and then create a folder of the same name in the same location. For e.g. If you create a folder named 'Photos' and then uncheck 'Photos' located in your selective Sync preferences, then this will stop 'Photos' from syncing to the Dropbox folder on your computer. If you create a new folder named 'Photos' in the same location in your Dropbox, then it will appear with a gray minus sign. Dropbox will not sync the new 'Photos' folder to your account. This is the Selective Sync conflict on Dropbox.
Quick Tip to ensure your Photos never go missing
Photos are precious memories and all of us never want to ever lose them to hard disk crashes or missing drives. PicBackMan is the easiest and simplest way to keep your photos safely backed up in one or more online accounts. Simply download PicBackMan (it's free!), register your account, connect to your online store and tell PicBackMan where your photos are - PicBackMan does the rest, automatically. It bulk uploads all photos and keeps looking for new ones and uploads those too. You don't have to ever touch it.